I wrote about the challenges of running a witness. In a nutshell, it's not just about running the server, there are numerous factors to consider if you want to be serious about it.

You can do a setup the easy way with @someguy's docker option (but that doesn't mean that it will be easier to maintain in case of trouble, if you're not linux savvy). Also @netuoso wrote a good guide on building/running it: https://steemit.com/witness-category/@netuoso/the-concise-steem-witness-guide-for-ubuntu-16-july-2017