Jintor, this one's for you!
Here are some details about my animation process for the beat'em all segment characters.
I'm not going into the principles of animation itself (rhythm, speeding up/down, keyframing vs. inbetweening, etc) as that'd be a whole other thing and others would do that far better than I (Noogy, I summon thee).
I'm just going into the thought process behind each step when I design/animate the first few moves for a new char. Hopefully it might help someone, and if not, it'll still count as a Honey update, so there!
First, I make the idle pose/animation. All of the other fighting moves fire off from this pose, so it's important I get it right soon. I find idles to be some of the hardest animations to do, since they're meant to evoke character, but mostly use slight and subtle movements (unless you're Elena), and slight and subtles movements are super hard to get right. Doing frame by frame animation, you can't really copy/paste elements of the whole frame for each new one, else it looks stiff, but you can get by drawing two different frames, and then alterning between those two for immobile elements to still get a vibrating effect. I tend to copy/paste stuff for those very slight movements, otherwise it's best to draw a new frame altogether most of the time.
Once that's done I move on to the walking cycle, as it's probably the second hardest. Some would argue walk cycles *are* the hardest animations to get right.
You'll see I'm only using the layers on the right, adjusting the opacity each time I'm making a new one, to create an onion skin effect. No other tools required for any of this!
Also, I suggest doing it part by part - instead of drawing the whole figure in one go, focus on getting one movement right (here, the legs), then move on to the next thing.
Once I end up with this I move on to adding the rest: first the head, to get the bobbing motion, then the torso, then the arms. There's still funny stuff going on with the neck/torso and ribcage, but for a sketch, it'll do. Know when to stop!
Now, for the fighting motions themselves. This is where the different fighting game concepts, such as startup frames, hit frames and recovery frames enter the play. This is the part you should design on paper beforehand.
Depending on how hardcore your fighting mechanics are, you can play looser with those rules: since Honey isn't a "fighting game", but a beat'em all in the style of Streets of Rage, the timings don't need to be as precise. I also tinker with the animation playback speed ingame based on your speed stat, so not all characters play their animations at the same speed - if you aim to make a balanced fighting 2P game, don't do that, and balance your stuff on paper first!
Honey as a character has medium speed, most of her moves average around 8 frames with a classic 3/5 ratio: 2 startup, 1 hit, 5 recovery. Big Blue, the character here, is slightly slower. The first kick, one of her snappier moves has 9 frames, for a 3/6 ratio and a slightly lower playback rate, meaning Honey should connect if she does one of her jabs during the first frame or two of BB's animation. I *could* test it ingame at this stage using my sketches, but the import process is long, so I'm working off previous experience from the other characters.
For this one I'm using a sped up frame for rhythm purposes: the third startup, with the directional lines, is 0.6 times faster than the others, making for a slightly accelerated rhythm as we go for the hit frame.
The intent for this hit is to have a short range and medium-long recovery, allowing you to get a hit in during the recovery phase if you're far away - however, there's a follow-up hit as well. This one is designed to fire off frames 5/6. So I'm using those as a new base (not idle) to design the second kick, leading back to idle:
...which has even longer recovery (and may even possibly miss a frame or two at the end to transition to idle more fluidly, but it's already 12 frames long, and I need to balance an adequate number of frames with memory constraints).
So with that I have a very basic moveset, from which all of the other moves can be designed and animated following the exact same principes.
The only moves in Honey that don't follow these guidelines are the grapples and throws, since I'm doing both characters in a single animation for depth drawing issues and... I don't recommend that. I won't be doing it again, either :-D
Hope any of it helps! If you have any questions regarding any step of the process, feel free to ask. As for tools, I've only used here the basic photoshop (or any other drawing software) layers+the painting brush. Animation timeline *can* offer previews of your WIP animations, but I kind of dislike it as it eats screen space.
Apologies! I'll fix the colors ASAP