concept: Don’t worry, I’ll be right back!
process: For this project, I really wanted hone in on the concept of “follow through” and I figured a good practice would be character animation.  So, I found a fun vector illustration on shutterstock; that I was able to separate in Illustrator.  And from there, it was really all After Effects.
I started by animating the feet; offsetting the keyframes for each foot.  Then I worked on the arms (again offsetting each arm), which lead me to the balloon, followed by the head bobble and the the blinking eyes.  I found this chronological method to be incredibly beneficial.  Because once, I had the feet animating right I was able to use that as a base to animate everything else.  (Also, because, I’m ocd and like working in a chronological way.)  The balloon and string were the trickiest pieces!  They are literally connected, but I wanted each to have it’s own weight and personality.  So, I ended up animating them separately - the arm leading the string which lead the balloon.  I just massaged those keyframes, really working the graph editor, to give the balloon it’s bounce and wiggle.
Lastly, I wanted to turn this into a looping GIF.  So, I made sure to have the same starting and ending frame.  And brought the character in and out of the frame from two different positions.  And… speaking of “follow through”, I separated the string even further to give a trail at the end.