-- Wash your hair only once or twice weekly, not every day. When you wash every day, you strip your hair of natural oils and conditioners just can't make up for it. I'll explain what to do on the in-between-washes days under brushing. There will be a period of adjustment at first! when you strip oils everyday your scalp starts to produce way more than you need, and it will take a little while for the oil to be the correct amount.
-- Use water that is as cold as you can be comfortable with. Hot water opens the hair shaft more, which makes it more likely to get damaged and also makes it lose color (if you have it dyed). It can also irritate your scalp and give you dandruff.
-- Do NOT pile all of your hair on your head and scrub around -- this really damages your hair (and creates tangles). Instead, apply shampoo only to the roots, and rub the scalp in small circles with your fingertips until it lathers, making sure the hair doesn't get tangled around your hair and pull. When you rinse, you'll run the shampoo through the rest of your hair and it will get clean -- applying shampoo directly to the older bits of hair will cause it to get damaged.
-- After rinsing, apply conditioner thickly at the ends and thinly at the roots, and let it sit for five minutes (ignore the bottle's instructions! your hair will be wet, and conditioner has a harder time getting into wet hair because hair acts like a sponge).
-- rinse completely! if you leave any on, it will sit on top of the hairs and make it feel stiff and sticky, and it will smother your scalp, which can cause dandruff.
-- if you want, apply a little leave-in conditioner after your hair is mostly dry (so that it can soak it up). I use Infusium 23 about once every 2-3 washes, or if I'm straightening my hair.
-- never brush wet hair! when hair is wet it's more stretchy and expanded, thus much more likely to break/split. If you want to untangle wet hair, use a wide-toothed comb and...
-- To remove tangles, start at the ends and comb a 2-inch length, then increase the length of strokes slowly until your hair is untangled. Starting at the roots makes the tangles all get pushed together, which means more damage.
-- On non-washing days, first comb to untangle. Then, take a wide bristled brush (like the 'vent' brush here) and unwind cotton balls to loop between the bristles. (alternatively you can wrap a soft-bristled brush in old pantyhose -- this works better for very short hair) Then, lean over and flip your hair forward, and brush from the nape of your neck to your forehead and down to the ends of your hair. Brush at least 50 strokes and try to spread them out evenly so that you are stimulating the whole scalp. This evenly distributes the oils so that you don't get the "greasy" look from oils all being at the roots. The cotton balls also help catch loose dirt and lint. (I tend to brush 25 strokes nape-to-forehead, 25 from left ear to right ear, 25 from right to left, and 25 straight back, but that's probably more than necessary)
-- if you have really short hair (less than an inch long), you can rub your scalp with a paper towel to absorb/redistribute oil.
BLEACHING & DYING (with demi-permanent colors):
-- after applying bleach or color to your hair, wrap your head in plastic wrap and blow-dry it on hot a little bit. The trapped heat will make the bleach/color develop more quickly and intensely.
-- after bleaching, rinse thoroughly but do not wash or condition (that will keep the color from absorbing as well). You can wash/condition if you're using a truly permanent hair color but not demi-permanents.
-- after dying, rinse thoroughly (until the water runs clear) but do not wash or condition for another 12-24 hours. This allows the color to set more so it will stay bright longer.
-- again, use cold water when rinsing/washing!
If you try any of this, lemme know how it turns out! And if you have any additional tips please share :D