Most naturals choose to detangle one of two ways:
The reason some naturals tend to opt to finger detangle is because it's gentler on the hair and results in hair that is more thoroughly detangled. The gentler you are on your hair the better length retention.
Some naturals finger detangle root to tip, others detangle tip to root it really depends on your hair and how it tangles. Bear in mind, finger detangling can be time consuming,
Using a wide toothed comb/denman brush
A wide tooth comb can be quite helpful; it is gentler on your hair than fine toothed combs. They tend to detangle the hair quite well and it takes less time to detangle your hair. Do bear in mind though that as these combs are wide toothed they may not detangle as well as finger detangling.
Wet or dry detangling?
You will hear a lot of people refer to how much 'slip' a product has, this refers to how easy it is to detangle with that product, so as you see many naturals tend to detangle their hair during the cowash process, or during moisturising their hair because their hair has 'slip' at these points in time. This helps to avoid exerting excess tension and friction on the hair so less hair is pulled out during the process.
Others prefer to detangle on dry hair using a natural oil, so there is no rule it really depends on what works for you.
Section your hair, detangle and handle each section gently
Take your time
Retwist detangled sections to keep them knot free
Stretching hair prior (i.e. have the hair in two braids) to detangling helps facilitate the detangling process