If you're a fine haired girl, oils and moisturizers don't tend to be your friend. They can weigh your hair down and make your normally non-frizzy hair frizzy. You want a lot of light conditioning that rinses off easily! Consider using cream rinse type products over intense or rinse off conditioners, and consider using detanglers over leave in conditioners. If your hair is really fine, you might be able to use a leave in conditioner as a regular conditioner (you can use it outside of the shower and use before combing!).
Humectants may or may not be your friend - you'll have to decide that for yourself - and you'll probably find you like the hydrolyzed proteins that film form rather than penetrate, so you'll want to stock up on oat or soy protein instead of silk. (My best friend has fine hair and she hates silk, but anecdotes do not make data, so I can't say for sure what your hair will like!)
When making any of the recipes I've posted, always leave out the cetyl alcohol - it's way too moisturizing for your hair - and replace it with water. Although my fine-haired best friend finds the 7% BTMS recipes work well for her, you might want to reduce the BTMS or cetrimonium bromide to 3% or so and replace that missing amount with water. (Having said this, if you add cetrimonium chloride to your conditioner recipes, it will thin out dramatically, so I do suggest using 7% in that case.)
I have included low levels of silicones in this recipe as even fine haired girls like the gloss, sheen, and lubricity silicones have to offer. If you don't like them, then remove them and add 2% water to the heated water phase.
LIGHT CONDITIONER FOR FINE HAIR
HEATED WATER PHASE
90% water or a combination of hydrosols, aloe vera, and water
2% hydrolyzed protein
HEATED OIL PHASE
3% BTMS-50 or cetrimonium bromide
COOL DOWN PHASE
0.5% to 1% preservative
1% fragrance oil
You can use the alternate instructions for conditioners for this recipe as we don't have a very large oil phase! And I realize this is very close to being a leave-in conditioner - a little more BTMS in this recipe - so you can follow those recipes and add a little more BTMS or cetrimonium bromide if you wish.
Feel free to add all kinds of wonderful extracts and hydrosols if you choose. And if you have cetrimonium chloride, add it at 2% in the cool down phase and take out 2% water.
As for leave in conditioners, I'd suggest using a detangler if you really need to get rid of knots! Join me for fun formulating leave in conditioners and detanglers over the next few days!