Hey Mero!
Welcome to Pixelation =)
It's definitely a good idea to start with pretty flat colours when practising animation. Something that also helps is to get a pretty open and naturally easy to move stance, especially when it's someone holding a weapon. It doesn't take a lot of frames to make something this tiny move, this edit I made is 4 frames.
The trick is, well it's not really a trick but sort of the idea with an idle is to calculate how much you can move the character to create a loop back to your first frame. I try to simply begin by moving the upper body either up or down one pixel, leave the legs alone for now. This will happen:
What I try to work with after that is to move single pixels, like her knee bending, you simply have to move it a few pixels at the time, take away from the right side and move those pixels to the "inside" slowly building a cluster where she will bend it.
The light blue pixels is where the previous frame were
As you probably can see I've moved some colours on the inside as well.
after that you want the sprite to land in the position where it's as far down as it will ever be. A trick when animating hair is to always keep it one frame behind, it will make it look light and give it a nice flow. So in your 2nd frame you want the hair to almost be in the exact same position as it were in the first, or even up a pixel to indicate she's pressing down, and you won't move the hair much until the character prepares to go "up" again. The 3rd frame is all about reseting the character smoothly back to it's original frame. I don't know what tool you are using, but there are software out there that lets you use Onion skin (you see a transparent image of the previous frame) which helps a great deal when trying to create a smooth loop, Graphics Gale is one of those.
I hope this can help you get a better understanding of animation. I could go on forever but the real lesson here is just to practise, practise and practise and eventually you'll feel that you're getting more and more control over the "limbs"!
