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?
Simple, just check their trading activities the more they have liquidity the more you can exchange at ease. Right now there are a lot of exchanges that use bots rather than real people, you will see the difference if an exchange that uses a bot or many real traders if you have some experience in many exchanges. The other thing is the security if an exchange provides a low security then just forget it, it's better to go to the top exchange.