Spli Testing - Advice Please

[muchacho]

I've recently got my account back up and running since the change in the UK and I'm doing a 'split test'. Could anybody point me in the right direction.

- How many keywords (maximum) should I have in each Ad Group?
- If one of my keywords gets a very good CTR does this effect the ranking of other keywords from within the same Ad Group?

If anybody knows a guide that they'd recommend following re: Split Testing, I'd very much appreciate it.

I feel it's imperative that Split Testing is used, as you are then always trying to better your listing.

Regards, Muchacho.

EDIT: Title was supposed to say 'Split'