Keith gives a pretty good summary of what's available and works.
Make sure the topical you are using is labeled for Ticks, many just do fleas. All topicals lose efficacy with time and the tick part is the first and quickest to quit.
I'd be real careful about using multiple products (topical plus spray plus shampoo, plus oral...) You can get to a toxic situation pretty easily with multiple applications.
I wouldn't recommend human topical repellants as they are not designed with possible oral ingestion when a dog would lick him/herself.
Your best prevention is to avoid the environment where you are most likely to get ticks (tall grass/weeds, off trail in the woods).
I've had some situations where I've suggested more frequent topical application or adding a permethrin spray (used sparingly) on top of the topical, BUT that decision is best made in consultation with your vet - they know the products you're using and your dog.
Doug, DVM