I'm in the same problem as you, having no idea what tracks I need to learn in order to not make a fool out of myself online.
I've obviously learned BL1 and BL1R when I had the demo. Now I focused on FE1 and FE1R and know them pretty well. It's a tiny map (should get to under 51 seconds with the XFG and XRG on it pretty fast) and it's fun. Now I'm going to go for Aston Cadet, Green, Club, etc. Those are small maps as well.
As my friend says, don't try to be a pro in a week. It takes time to memorize and become better. You'll suck and you'll hate it, but that's how it works. Slowly, you'll stop sucking.