Same problem here (fine density).
When i want more voluminous hair:
I wash hair as usual, squeeze excess of water then put a towel on my hair for 10-15min.
Then i comb it with a wide toothed comb and style as usual.
I blow dry with diffuser.
This routine give me a good volume but less definition and medium frizz.

When i want clumps:
I wash hair as usual, fingercomb when hair is condish-full.
I rinse, squeeze excess of water then put a towel on my hair for 10-15min.
I style as usual and then i diffuse following the pixie method.
This way i achieve a good amount of clumps and minimum to none frizz.
Curl Pattern: 2c-3a
Porosity: medium
Density: thin
Width: fine
Lenght: short (jaw-lenght)
2013 haircut: 1/25/2013; 07/04/2013

Routine: modified CG
CW: cone free and protein free conditioners
DT: homemade sheabutter hair creme /Hydraderm sheabutter hair mask+coconut oil+lecitin
Styling before diffusing FSG with hydrolized keratin
Once a month (or every 2 months): henna