@sherry lambert,
At the last company I worked for they made me do a lot of IQ tests to do some internal benchmarking and I ended up learning a lot about the IQ testing services that employers used.
If you are familiar with the common types of IQ test questions you can improve on it slightly, but the best advice I can give you for most of the corporate IQ tests I have seen is to just work fast. I've found that in most of the tests I took repeatedly if I'd skip anything I couldn't immediately see the answer for within a few seconds it would make a pretty big difference in my score. It was better than getting a fewer number of questions all correct.
So if you see a timed element to the test where there is not a fixed number of questions and it will let you answer as many as you can within a specific time frame then just go as fast as you can.
But all of that said, you should realize that they are trying to measure innate intelligence and you aren't supposed to be able to improve your scores that much. You certainly can, because the tests aren't perfect and if you do enough of a certain type of pattern recognition you begin to regognize meta patterns they use to make the questions, but this is the type of test where you can't do much to ace it.
So if you want to get slightly better scores: take a lot of IQ tests and get good at the kind of spacial logic and pattern recognition questions they ask, and then when you are taking a test don't fret the individual answers too much and try to answer the ones you can quickly.