How to get my hair to grow thick and fast?

Answered:
Let me start by stating that there is not a shampoo or conditioner that promotes hair growth unless is it prescribed by a physician and contains either "Rogaine" or "Minoxidil", or Propecia.
Normally you will lose up to 100 hairs a day. The most common reasons for hair loss is ether medication, stress, or illness. If you feel your hair loss is excessive you should see your doctor to make sure it is not caused by the latter.
The only way you can grow healthy hair is to eat a healthy diet high in protein (Hair is composed of keratin hard protein.) and take prenatal vitamins. (If you are a woman.) I had a client on prenatal vitamins and her hair grew twice a fast as normal. It normally takes about 4 to 6 weeks before you start seeing results.
Do not forget to exercise regularly. Not only is it great for you but it will get your blood flowing and feed the follicle fresh oxygen.
Hair usually grows to inch every 4 to 6 weeks.

Shampooing
When you shampoo your hair you should manipulate your scalp vigorously.
In order to grow healthy hair your scalp needs to be clean; by not shampooing you are defeating your efforts to grow healthy hair. I recommend shampooing every other day using a shampoo for chemically treated hair; even if your hair is not chemically treated. Shampoo that has been formulated for chemically treated hair has less detergent than a shampoo that has been formulated for normal hair. Detergent will remove to many natural oils and cause your hair to be dry.
Shampoo will not make your hair thicker. In order to do this the shampoo would have to create more hair follicles on your scalp; man cannot create a hair follicle

Split ends
Also you need to have a trim every 6-8 weeks to prevent split ends. A hair follicle that has a spit end is damaged beyond repair. If you do not have your hair trimmed to get the split end off they will eat there way up the hair shaft like a pac-man. There is not a shampoo or conditioner that will repair split ends. The only repair for a spit end is to have it cut off. While there are shampoo and conditioners out that make the claim of repairing split ends all they do is put either a wax or plastic coating over the hair shaft; when the coating wears off the spit is back.
The only way to thicken your hair is to have either a hair transplant or extensions: man cannot create a hair follicle.

Thickening
There is not a shampoo or conditioner that will make your hair thicker. In order for this to happen the shampoo or conditioner would have to create a new hair follicle in your scalp. Man cannot create a hair follicle.

In closing let me state that trimming your hair will not make it grow. Hair does not grow from the tips like grass; it grows from the roots.

I have been a licensed, practicing cosmetologist for 36 years +.
Hope this helps.