So I see you are new to Pivot and you will find out that it gives you a big range of abilities.
Animating isn't a thing that you learn withnin a few minutes. It takes months of practice if you want to become really good.
Here are some basic things you will hear in your time as an animator:
Choppyness describes that the movements don't look fluid, they rather look "chopped" off because they aren't stretched over enough frames. Make sure to move the men a little bit in every frame, this will eleminate the choppyness.
Stiffness means that the stickmen don't look real because they are stiff. This happens when you don't move
every part of the stickman in every frame. If he moves his arm, his upper body will be affected, too. And then, the further away the part is from the actual movement, the smaller the affection will be. It
has to be noticable, though.
Easing is used to describe the tactic that the stickman moves slow (only a little movement in every frame) before he starts a fast action, then it keeps on going faster (the space in between the frames becomes bigger) and WHAM! From the "WHAM!" on, he'll then slow down again.
I hope I helped you a little bit. There's the thread we have here where Beginners like you can post their animations and give each other constructive critism. Please post your animations there. If you don't, people may get mad at you and you will become pretty disrespected. You can find that thread
here.