I figured I would write an extensive guide answering some trading questions and explaining how people should choose which fighters to trade for.
This is more geared towards newer users who are trying to create a team, and need a way to figure out how to get powerful fighters decently quickly. I basically wrote this out because I've seen quite a few people go "where should I go next with my team?" and hopefully this will help the indecisive be a bit more decisive.
The first section covers choosing what to pursue, the second section has some common Q&A.
- 1 Resources
- 2 Goals
- 3 Common Questions
There are three important places that you should use to supplement your trading (along with this forum, of course!):
- 1. The Wiki
- 2. The Fighters List
- 3. The Community
The wiki has a lot of useful links, and you can search any fighter's name to find out more information about them. If you don't know fighter names by heart yet, or want to know what evolutionary line a fighter is in, you'll want to search it up there.
The Fighters List is a sortable spreadsheet with all the fighters. You can quickly sort by, say, epic --> champ and then by total stats, highest ATK, etc. This can help you get an idea of where a fighter you're interested falls in terms of strength.
The Community is a clump of friendly D.o.T. veterans and beginners who you can always fall back on for support and advice. Feel free to join us in chat and ask us questions!
TLDR: Always aim to acquire epics that you will eventually max SEF. For people starting out, the easiest epics to max SEF are those that are more common but have lower stats -- typically hero fighters. The class with the most utility at the moment is rogues.
I won't go through the most basic of basics (how to make an offer/trade). You can see an overview of that on Trading.
What I will start with is the most important part -- figuring out what to focus on and whether it is viable or not.
"How do I choose which fighters to trade for / focus on?"
You need to know what you want in order to focus your 5 offers/5 trades a day to create something useful! Now, the answer to the above question will obviously depend on your current team, and your goals for the game. If all you have is rares, you may be more concerned with finding 6 of a rare to get a single epic going. If you have quite a few epics, you may be interested in figuring out which one to max SEF. Regardless of where you are in the game, remember that you will want to focus on fighters that you can eventually max SEF. Fighters that are not max SEF have higher proc counters (thus typically making rogues/guru a lot harder to use) and, obviously, lower stats.
"All right, I've decided! I'm going for the weeklong rank reward that came out ten events ago, because it has awesome stats and--"
Hold on there, buddy! Now, when deciding what fighters you want to focus on, obviously the best-looking ones are the ones with the highest stats, etc. But you need to go for something you can easily max SEF. That's why I recommend using the wiki to check whether the fighter is available through pixite/voxite (which will typically mean it's not limited, and thus may be easier to acquire over time) or whether it was a hero fighter or rank reward.
Hero fighters are special fighters that get an extra EDGE during the event they were introduced in. They are typically weaker than their rank reward counterparts, but they are also typically far more abundant and easily obtained. Rank reward fighters are fighters rewarded for placing high on the leaderboard, and they typically have good stats to boot.
My rule of thumb on how to tell how good an epic is: if its main stats (ie the stats pertinent to its class, so WIS/AGI for guru, for example) are in the 4k range, then it is a good/normal epic. If its stats are below 4k, then it is one of the weaker epics, and if its stats are above 5k, then it is probably going to be one of the top tier epics one way or another (see: Boldewin with his 7k WIS and 5k AGI).
I suggest that, if you're new, you pursue hero fighters. As mentioned, they are more readily obtainable, and you can most likely get them for fairly cheap on the market. A max SEF hero fighter epic will be far more useful than a 0/5 or low SEF of a rarer, rank reward epic. Not only that, but a max SEF hero fighter will still be useful in its sign/tribe/class EDGE dungeons, more so than a non-SEFd fighter, even if that fighter has high max stats. Alternatively, you can also trade for pixite/voxite-obtainable fighters that evolve up to epic forms, as people are sometimes more willing to trade those away than rank rewards and they may be easier to obtain.
Therefore, let's say you've just finished a dungeon event or a weeklong raid event and you have a couple of the rarer rank rewards. It might be a good idea to trade those of for the more common hero fighters, because your goal is to max SEF some epics to help you out later on. Once you have a strong team, you'll be better equipped to take on dungeons/PVP/etc and thus earn better fighters or trade fodder.
"What class should I focus on?"
Once again, this depends on what you have, but my personal recommendation would be the following:
- Max SEF'd rogues are useful in almost any situation, as they can kill guru (or even champs) in PVP, and they are good for dealing damage in dungeons.
- Max SEF'd guru come in two basic varieties: those with single-target attacks and those with multi-target attacks. Those with single-target attacks typically proc their skill every turn at max SEF. Usually with EDGE, this is definitely enough to take one fighter out, so they are their most useful when you have several lined up. Multi-target guru skills proc every other turn at max SEF, so they are good to stagger (either with another rogue, or several other guru).
- Champs are decent at both dungeons and PVP, however the best strategy in the game right now seems to be to kill things first before they have a chance to touch you. That said, there are a lot of different types of champs available (many are quite easy to acquire) and they can have some interesting uses in your team (tanking a rogue, for example, and then killing it afterwards) so having a couple of these is a good investment for newbies as well.
"Okay, okay, what about the actual trading?"
Based on what I've just said, I recommend that you try to acquire as much "trade fodder" (fighters you plan to trade away) as possible during dungeon or PVP events, and then decide on one (or two) fighter lines to follow and attempt to acquire. Remember, make reasonable offers and someone will probably take you up on them. If you're going for a dungeon hero fighter (or even rank reward), then you can probably offer up one of the other two hero fighters in a one-for-one trade in order to acquire it. In fact, people might even be able to trade their epic hero fighters for a couple rank rares, or whatever it is they are looking for.
This section details some common questions I've seen pertaining to trading.
"When's the best time to sell/buy this fighter?"
The market fluctuates, so prices, supply, and demand are constantly changing. If you have a raid fighter that has EDGE the next raid event, then you might want to try selling right before the event starts or even during it.
After dungeon events end (and event fighters become tradeable) is when several things happen: 1) you can snap up really good deals for the fighter you're interested in, as people will be putting a lot of offers up and some of them will be undervalued, and 2) this is when people will be trying to SEF up the newly introduced fighters, so if you want to sell an event fighter, you'll have more visibility then.
"Should I SEF this fighter or keep it separate?"
For trading purposes, I recommend you keep all your fighters separate unless you are actively using them in your band. Sometimes people will ask for 2x of a fighter, but if all you have is a 1/5 SEF, that only counts as one fighter. Likewise, if someone posts an offer wanting one [fighter], then it's better to trade away one that is 0/5 SEF instead of a higher SEF.
If you're working towards building a max SEF epic, but you're not entirely sure if you'll finish it or if you'll sell it off before then for a better deal, then I would recommend considering SEFing only when you can hit a 2/5 SEF for fighters whose skill counter will be down to around 1 then (single-target guru and rogues). Sometimes it's harder to get a good deal for a higher SEF'd fighter.
"Is this a good deal?" 
In order to figure out if a trade is a good deal, first look at if the trade is of close value (about 5 bitters) to other trades. Keep in mind that one nux is commonly valued as 2 bitters. If you can't determine from that, ask yourself, "do I personally think that I should do this trade?"
"Why can't I seem to be able to trade this fighter?"
The fighter must not be an event fighter during the event it's introduced, common rarity, levied, or locked. Epics are auto-locked when acquired, so unlock them before you trade them.
"How do I not get scammed?"
The most common form of getting scammed at the moment is getting a lower SEF fighter than you were originally promised. Thus I recommend that you either don't do high-SEF trades, or that the person promising to trade you a high SEF fighter is the one to put up the offer, so that you can verify the SEF. I would also advise against multi-part trades (for example, 2 of your fighters for 3 of theirs kind of deal) as you can end up with only half of what you bargained for.