You'll need a server with at least 16GB of RAM.

I used this guide, and got help from people on the #witness channel on Steemit.chat when I was in trouble.

It doesn't matter how much SP you have, it matters who votes for you. I'm not in the top 100 witnesses (therefore not producing blocks) yet because I don't have enough votes yet. It looks like I'll need nearly 500MV of voting power supporting me before I can create blocks, you'll need the same.