I totally agree with this and with the comment about getting the right cut. I would add that advice to try limiting the amount of product you use and/or using lightweight products. I would apply only what you need to keep your hair moisturized.
Once your hair is dry you can increase volume by gently pulling out the roots using your fingers as a comb/pick (some people use an actual pick). If you choose not to diffuse it helps (me at least) to flip the hair upside down a few times during the air drying process and scrunching the curls upwards. All of these things increase volume very well. If your hair is naturally thin/fine you may need to finish with a hairspray to hold the volume you've created.
3c/b, medium density, medium texture, low-normal porosity.
: TN Nourishing Moisture Conditioner
: DevaCurl Styling Cream or Golden
: Jane Carter Solution Nourish and Shine
: DevaCurl Heaven In Hair
Water-wash and go 2x/week, no poo 1x/week, DC 1x/week
since 3/31/12; patiently growing my (unstretched) curls to APL (again