>>2406551so this is the tedious part since you're basically just repeating the previous steps. the first thing i do is draw the legs, since you would have coloured over them in the previous step. what i usually do is I use the pen tool to draw curved lines but I turn off "simulate pressure". then i use the eraser tool with the size set to something massive and hardness set to 0%. I then place my cursor far away from the line I just drew and tap a few times. this will lightly erase the end of your line which makes it fade out naturally. you can experiment with smaller eraser sizes and placing your cursor closer to the line to make it taper off quicker. this is another reason why you make a new layer for everything; if you drew the new lines on the same layer you used for colouring you would end up erasing your colour.
sometimes the pen tool can be a hassle to use and manually redrawing is better. in that case you'll want to look at these two options (in the pic). Smoothing basically just smoothens out your cursor movement when using a brush-type tool (like brushes, erasers etc). it'll make your lines lag behind the cursor but it gets rid of any hand tremors. if you use a mouse this is pretty useful.
the second option is pen pressure which is only really relevant if you have a graphics tablet, it makes your lines darker if you press harder into the tablet. i'm just using a really cheap tablet I got for like $30.
you might also want to draw light on some parts of your character to simulate shadows being cast on it by other objects. you can do this by using your pen tool to select part of your character, right click -> make selection and then use your brush tool with a lighter colour and paint in that area. you can look at the light and shadows on other parts of your character (that the animators already drew) to figure out where you should draw light, but desu i just kinda pick random spots since it's just fap material anyway.