If the job of waterproofing your basement is a larger problem than a few coats of UGL, then you may want to think about hiring a contractor. You can get a listing of contractors from the National Association of Waterproofing and Structural Repair Contractors. Here are some ways to assess the potential contractor's skills:
Was there a thorough inspection done of your basement and water problem?
Was there an in depth explanation of what the contractor intends to do to correct the problem?
Was the estimate in written form and delivered soon after the inspection?
Were written warranties provided as well as references and a Right to Cancel form (giving you the right to cancel the contract within three business days) ?
Was the contractor insured and licensed?
Was the contractor's behavior professional and trustworthy?
It is important to check out the contractor with the NAWSRC as there are individuals that use a homeowner's lack of information to take advantage of them. Make sure they are certified with the NAWSRC that maintains standards for their members as well as an ethics code.
Determine where the moisture is coming from: either inside or outside. If inside, vent or remove the moisture producers such as a shower or stove. If outside, make sure the gutters, downspouts and landscape grading are doing their job of directing water away from the home. If there are larger problems that a waterproofer cannot accomplish, call in a contractor to assess the specific issues.