I was a QA many years ago, for about 5 years. Here are my tips:
1) It doesn't matter which test suites you use - I wrote my most valuable tests in straight Perl (ie no test suite)
2) The most important aspect of QA is communication with developers. Don't just log bugs and let devs fix it in their own time. Have a chat with at least one dev a day at their desk. Watch while they fix the bug - turn it into an almost social, non-pressured action. Many bugs can be quite traumatic to developers - your work is to soften this. Take interest in the code you're testing.
3) When you find an issue, only then start testing the issue. For each issue, try and find out as much as possible about the issue by testing it in as many as possible states, with as many as possible input sets. Try everything you can think of. Also try very hard to find a workaround for each issue. A lot of information about an issue is embedded in the workaround.
4) Never stop hand-testing. Never stop refactoring results of your manual tests into your suite. Treat your test suite as a product in itself, and log bugs on it.
5) Mastering QA will turn you into a better developer. You'll pick up good habits which you will never be able to shake again. You will write robust code. Above all, you will be able to communicate with QA.