Yes, The right steps should be followed if one wants to grow long hair. As I told you earlier, that it is a long term commitment. If you have to grow about 8" - 10" of hair, most probably it'll take about 12 to 14 months. For some it may be quicker as per their genetic trait.
The length of hair is hereditary, which we can't change much, but what we can do is to look after it nicely and carefully so that we get the maximum length we can get and maintain it healthy and shining.
It is very very important that we take care of our diet. It should be nutritious , full of vitamins, calcium and proteins. Always add foods rich in proteins and calcium like milk and milk products, dry fruits and nuts, fresh fruits and green leafy vegetables.
You have to drink fluids, so that your body is able to flush out the toxins and waste material regularly and clearly. Only if your body is healthy, you can have healthy glowing face and hair.
You have to minimize the use of heat on your hair. Unless necessary and unavoidable , do not use hair driers, curling irons or straightening rods. These things spoil your hair roots and make the hair dry and brittle. It'll get you split ends and that is the worst enemy of long hair.
You have to be very careful with these split ends. Trim them off now and then to maintain hair growth but then the growth will get slower but the hair will be healthy and thick.
Avoid tension, be relaxed at all times. Keep your calm, if need be, then meditate for sometime in the mornings to keep tension far. Get at least 8-9 hours sleep daily.If you look after your health well, your hair will also be healthy and will not give you any trouble.