One of the more frustrating things about tutoring is when students or their parents want to treat tutoring like a quick fix. In other words, sometimes they want to meet the night before a test and cram for said test in hopes of getting a better grade. On the surface, this problem might work, but it treats the symptoms rather than the root of the problem.
If you're going to take the time to invest in a tutor, then here are a couple of suggestions.
First, try to catch the problem early. If you (or your child) is struggling in a subject, get help right away. Don't wait until you (or your child) feels that overwhelming feeling that comes when one is completely lost in information. The sooner a tutor can get involved, the better the tutor can help a student to stay on track.
Work with your tutor to adopt a thorough approach to the subject. It is not enough to learn the facts of a subject, but also to learn the reasons behind those facts. If you want to do well in a subject, you need to know it well enough to explain it to someone else and that should always be your goal. Sometimes, it takes a bit longer to get through a particular part of a subject with this approach, so it does take patience and perseverance, but it always pays off.
Finally, communicate with your tutor. If you feel that your tutor is moving to slowly or too fast for you, or if you don't understand the approach your tutor is taking, let them know. I cannot emphasize enough the importance of keeping open communication with your tutor. It is your tutor's job to help you (or your child) succeed, but a tutor can't do that if there are outstanding concerns he/she doesn't know about.
In conclusion, contact a tutor as soon as possible, resist the impulse to seek quick-fix tutoring, and communicate with your tutor.