You can try cloudflare,Zen protection or you can buy hosting with bulit-in Ddos protection
CloudFlare is the one and only thing I depend on. I buy with there Pro. I also know that Omniscient uses CloudFlare on a few of his bigger sites as well.
Use litespeed webserver, DoSDeflate, software firwall.
If your using apache, use mod_evasive to help block attacks.