Gentle Shampoo and Conditioner 2-3 times per week (MUST BE SILICONE AND SULFATE FREE)
RECCOMENDATIONS: Trader Joe's Tea Tree Tingle Shampoo and Conditioner, O'Douds Shampoo and Conditioner

THOROUGHLY RINSE AFTER SHAMPOOING, LEAVE CONDITIONER IN YOUR HAIR FOR 2-5 MINUTES

If your hair gets greasy on the days you don't shampoo, use a dry shampoo
RECCOMENDATIONS: Lush No Drought, Batiste Dry Shampoo

Clarifying Shampoo every 2-4 weeks (THESE CONTAIN SULFATES AND ITS OK)
REASONING: Clarifying shampoos are a reset switch for your hair and scalp. If you put any kind of styling product in your hair, and/or the water where you live is hard, this is necessary.
RECCOMENDATIONS: Neutrogena Anti-Residue Shampoo, Bumble and Bumble Sunday Shampoo

Everytime you shower, gently exfoliate your scalp with a scalp brush. When you shampoo, work the shampoo into your hair and scalp with the brush. Use the brush on days you just rinse with water as well.
RECCOMENDATIONS: Scalpmaster (Amazon has these)

Speaking of showers, DO NOT TAKE HOT SHOWERS (warm is okay, just nothing you wouldn't put a baby in), they dry your hair scalp and skin out like a motherfucker. After the shower, do not roughly towel dry your hair, this causes damage. Gently pat out as much water as possible and let it air dry. If you'd like to blow dry, which is also useful for styling, ALWAYS USE A HEAT PROTECTANT (RECCOMENDATIONS: Bumble and Bumble "Blow Dry" line)

And while we're on the topic of water, drink a TON of it, and you will see improvements in your hair and skin. Try to eat healthy as well, Biotin is necessary for hair and skin growth.

And last but not least, styling, which I assume is important to many /fa/ readers. The most important thing here is to avoid cheap products with harmful ingredients, avoid "mallcore" brands like American Crew. The products that won't harm your hair are small batch home brewed stuff mainly, /r/Pomade on reddit and the "Everything Pomade" Facebook group are great resources, there's a ton of stuff out there.