I get the best detangling on damp hair. Combing dry is leads to breakage. Combing wet causes the ends curl up around each other, creating tangles. I haven't worn my hair out for a while, but when I take down my cornrows I get the best and most effective detangling when I do the following:
1. Loose the cornrows out. Keep the hair dry, do not comb or finger comb. Just release the cornrows.
2. Wet a wash cloth or small towel. Squeeze out the excess water. Take sections of the hair and squeeze the hair between the washcloth. This dampens the hair.
3. Add some conditioner to provide slip. Just a little, too much causes the hair to get "wet."
4. Carefully section out a portion of the hair and detangle with fingers. Once all the tangles are out, detangle with a denman brush, starting from ends and working up towards the roots, to remove the shedded hair.
5. Use clips, bantu knots, or plaits to secure detangled hair.
6 Repeat steps 3-5 until the entire head is detangled. Re-dampen sections, if necessary.
Note: When I had small twists in my hair, I reversed steps 1 and 2.
After I do the above, I usually section my hair into four quadrants and then proceed to clarify, henna, deep condtion, etc.