what to do to prevent ticks on my dog

For preventative repelling and killing ticks on the dog, take a look at the active ingredient in the Preventix tick collar. My vet recommended it for the times we go into an area favorable to ticks. So I did a web search on the product its testing was surprising effective. Doubley so for me because after learning flea collars are pretty ineffective, I figured collars were generally a waste of money.

This Spring my dog has picked up a couple of ticks (not wearing the collar) and so I just put on a topical for fleas and ticks with pyrethin in it. Its prescription, but Frontline is pretty good and not perscription. (Fleas are easy to to pick up around here, so the dog always gets a topical but usually Advantage but that does nothing for ticks).

Best method I've found for removing the buggers if you're not real adept with the tweasers is to make a 'remover'.
Start with an old 35mm film canister (or similar plastic item).
Cut a v-notch in the rim about 1/4" deep.
Cut a thin slit at the bottom of the notch about 1/4" further.
Slide the notch along the skin and catch the tick at the head and this way you don't accidently squeeze 'em.
Remove tick and drop in alcohol.
Then usually I'll lay 'em on a paper towel to make it easier to ID them.
Some of the State extension offices have good bulletins [ame="http://entomology.cornell.edu/extension/medent/tickbiofs.cfm"]like this one from Cornell in NY:[/ame] or [ame="http://ohioline.osu.edu/hyg-fact/2000/pdf/2073.pdf"]this pdf from Ohio State[/ame]

Like someone already said, there's a bunch of different types of ticks depending on where you live. So it helps to figure out which ones are the problem, what diseases they carry, and what habitats they like (so you can alter them or be ready for when your dog may enter them).