Rooting,Custom Roms and Bricking !!

[rickson23]

hello guys,Last week I rejected 25k offer for my galaxy S2 bcz I love this phone ...and now I want to Root my S2.
I'm following Rooting Procedure tutuorial on ( How to root your Samsung Galaxy S2 | Reviews | CNET UK ).Any1 followed this one?
I know that Incorrectly Rooting may brick the phone.
I plan to use CM9 custom ROM, "My query is whether loading ROMS in future can cause bricking ? or bricking happens only during Rooting?

 

[rickson23]

Before installing zip from sd card?
Should I
1.reset factory?
2.reset cache
3.dalvik cache?
I have premium ROM Manager installed.