Just speed him up and then at certain parts slow him down, that way it looks smooth withiut having to be smooth, also watch some of my stick fighting and you may notice that they slow down and then when they attack or do big movements it happens quickly

When something first starts moving it starts off slow and then speeds up and slows down eg. A car also when animating jumping they slow down once they reach the maximum height and speed up when falling down? I'm not a good teacher I've already tried teaching someone but I'm better at learning than teaching so just practice animation different things. Here are a few good ones, a car, a jumping person, different types of balls (because some are squishy and bounce high whereas some are sturdy and don't bounce high), a person running (remember they start slow and speed up and when they finish they slow down before stopping, same goes for the car), flappy bird🐤 I say this because I noticed when I play flappy bird he goes up quickly and then slows down and then starts falling fast