This is newbie talk, so don't kill me. I want to learn, but it seems so complicated.
I want to - sell BTC for ETH, and then sell that ETH for more BTC than I started the trade with. Sounds like a simple way to start, yet I know it won't be.
My biggest concern is that there are so many exchanges. How the heck do I know which ones will pay me after I make an exchange? I know I have to check their reserve balance, but what else should I look for?
If it's not a lot, and if you are comfortable using a centralized exchange, then use a centralize exchange to make the trade. There are some exchanges that you can use without verifying or passing KYC as long as you don't deal with fiat currency. Or you can try using an instant exchange. The rates are usually the worst though, but faster and easier to use. If you don't feel comfortable using a centralized exchange, use a DEX but you will have to know somethings which are simple but might sound complicated. Google some exchanges and read their reviews.