You can start by shampooing or clarifying your hair. For a deep conditioner, you could either use an expensive deep conditioner like Frederic Fekkai Hair Mask to inexpensive types like Elasta QP Remoisturizer. What I do is apply the conditioner to the hair in sections to ensure proper coverage and cover with a heat cap, which helps to heat up the deep conditioner with your own body heat, or sit under a dryer or use a hand dryer for up to 5 minutes. Then rinse the hair thoroughly when done.
Using heat allows the conditioner to soak in better by expanding the hair shaft. I found that I got much better results while using heat. The deep conditioner penetrated more and my hair looked and feels better. Without some type of heat (heat cap or dryer) the deep conditioner just sat on my hair. I suggest one week you try without heat and the next time try with heat and see how your hair reacts.
For people who concerned with using heat on their hair, using a little indirect heat for deep conditioning once in a while is not the same as using direct heat appliances such as hot combs or flat-irons.