Wavy and curly hair already have texture. So creating texture with razoring or thinning shears isn't necessary. But you do need to remove some of the weight and bulk so that the waves and curls are allowed to curl! If I am doing a DIY wet cut, I don't hold the layer I am cutting more than approximately 90 - 110 degrees from my head. Usually I cut them holding them perpendicular to the floor. For a DIY Deva cut, I wash and style my hair, but leave it mostly naked (with just a LI conditioner) and snip where I think it needs to be snipped to remove any bulkiness.
To show you the dramatic difference a cut can make, below are some pictures from most recent (DIY Deva) haircut.
|Before my cut. 2nd day, slept on mostly naked hair.|
|After my cut. Waves were springier, and much more full looking while not taking a lot of length off. This was directly after the cut. No refreshing. SO it was still 2nd day, slept on, mostly naked hair!|