You can read about CloudFlare's benefits here. And Russian version of this post here

First you should set CloudFlare's name servers at your domain registrar.

This is you CloudFlare's Nameservers

This is your example of registrar's Nameservers

After that you should set A name at CloudFlare , if you use main domain as a blog. Or CNAME, for subdomain.

I've set CNAME only, 'cause I use subdomain:

More information about custom domains is here.

Обзор Mailbird. Самый быстрый почтовый клиент
Хитрости Postachio. Как настроить DNS для работы с CloudFlare