Tourette's is often a co-morbid condition ( happens along with another diagnosis).
In my sons case, (for those who don't know me, Gavin has Aspergers, and is 14) while he had some tics that came and went since he was very young, the actual Tourette's syndrome came at age 8 after a series of strep infections. His tics became very pronounced, with whole body movements, and because of the strep involvement, the doctors thought he had Sydenham's chorea at first, which is a rheumatic movement disorder.
When his rheumatoid studies all came back negative, they had us see a neurologist, who diagnosed something called "PANDAS" which stands for 'pediatric autoimmune neuro-psychiatric disorders after strep'. According to this doctor, there is a significant incidence of Tourette's and OCD presenting in children following strep infections, even in children who had no tic activity before that.
We also had no improvement with clonidine. We did have significant improvement with a drug called Orap, but later had to discontinue it as Gavin is allergic to penicillin, and Orap cannot be used with many other antibiotics. So, every time he had an infection, we had to first wean him off the Orap for a week before we could start antibiotics.
Currently he is not taking any medication for his tics. The medications had more side effects than usefullness, and as he has gotten older and comfortable with himself, he would rather not take them. When he has a tic that is painful, he usually can compensate by finding another movement that uses the same muscle group, or that causes the same sensation, although there are some times when this does not work. Although he is never without some kind of tic, they change all the time, and so if there is one that he can't alternate with something less painful, he at least knows that it is temporary.
My favorite web site, which helped me greatly when Gavin was first diagnosed, is
http://www.tourettesyndrome.net. There are great definitions and explanations under the conditions section. There is a parent introduction, and some poems by kids with Tourette's. This site has a huge amount of info on Tourette's as well as any other disorder that can accompany it.