It all comes down to figuring out your system... I could tell you what works for me, and in some cases, it would work for you too. But sometimes, what works for me, doesn't work for you and vice versa. Case in point, I was helping a friend brew a batch of beer on his system, while another friend helped him brew a second batch on the system he hauled over. Using a stainless kettle versus an aluminum kettle caused some radically different boil off rates, very little boil off in the stainless on one burner, and a great deal in the aluminum on another burner. Both boiled at about the same intensity...
So, I guess what I'm really saying is that we all went through this initial "figuring things out" stage in brewing. Don't get discouraged, and definitely take advantage of the forums, but figure out what works for you.
By the way, I love the Fermcap-S Foam Inhibitor, it not only keeps the kettle from boiling over, but also keeps my beer from escaping out the blowoff tube! Just my two cents. : )