Agadir
Thickening shampoo with argan oil works very well. It can help thicken the hair temporarily if that is what you are going for. Couple that with a nizoral for a couple days a week and you have a great mix.
Yes
Considering it is mostly genetic, the few things you can do is have a very balanced and healthy diet, as well as getting some exercise. Still then, it might not even do much of anything at all.