I have really thin hair and want to make it grow faster and thicker?

Use FDA approved. For men, the only fda approved medications available are rogaine (and generic minoxidil) and propecia (finasteride). Other fda cleared treatments involve the use of topical laser light to stimulate follicles.
Stimulate with laser. I find the best treatment is stimulation with a specific laser device called low level laser stimulation. Many devices are available, as a brush, stand, and lasercap. They have different strengths and convenience and need to be used regularly, especially if you have genetic hair loss. Best to start while you are still thinning, once bald patches happen, it's harder to reverse without surgery.