I don’t think you can speed up hair growth. It is a natural process and it will grow on its own speed. What one can do is help the growth. First thing is to lead a healthy lifestyle. Eat proper foods with lots of nutrients. Avoid junk foods. Sleep at proper time. Avoid stress. And keep your hair clean. Stress is a thing which totally hampers your body and it does cause hair fall. People travelling for work face hair fall because dust and dirt just gets accumulated in the hair and it weakens the hair strands so always cover your hair with scarf or kerchief while travelling.