Webfooted

What should I be looking for in a spinning reel? What are important things that I should look for?

Also, what is the little switch on the reel that says 'on' and 'off'?
And just one more thing, is there any way to make the handle that you rotate on the right side? I'm used to have having it on the right since I was used to a push-button rod before.

Thanks for any help.

Tags: important things, push button, spinning reel