That's 1/2 of the answer. I always try that first because most of the time that'll do it.

If you're not getting good results using just that half here's the rest:
1. Shifter and number of cogs on the cassette have to match. (Easy to check.)
2. Fresh, clean shift cables and housings. (If in doubt, throw them out.)
3. Derailleur hanger alignment. (On a 9-speed cassette this takes a special tool. Don't skip over it because it's a very common problem.)

ps: Limit screws are almost never the issue.