If you're rendering to upload, render it out as a Quicktime with a .H264 Codec, this is a pretty good codec in terms of file sizes and quality.
To put it in really basic terms though, it took me a few months of messing around with different settings to get a hang of what codecs output gives what looks, it's a hassle and probably one of the most annoying parts of editing/motion graphics because if you have a slow computer like me, then rendering for 12 hours, then realizing the file is 55GB and looks like shit is really annoying.
What you should do is limit or workspace to about 10 seconds, and render out a BUNCH of different formats and codecs and see what works best for you, personally this was the best way for me to learn.
If you're too lazy to do that, then go for the Quicktime H.264 or Photo JPEG at around 90-95 quality.
Good luck.