I would say to get a Q-tip that is saturated in alcohol, and dab it onto the tick's head. The alcohol causes the tick's mouth to become more relaxed and helps prevent the head from breaking off when removing it. Then just use a pair of tweezers, grasp the head firmly and pull it off.
As for prevention, really the only way your ball python is going to keep getting ticks is from being exposed to them. Its possible that if you take your ball outside a lot it could pick them up. I suppose its also possible that if a human or another animal could have carried them into your home and somehow ended up in your snake's enclosure.
Are you positive they are ticks? And was your snake imported (wild-caught)?