I went that route a few years ago. Few basic things I wish somebody had told me:
- While you're growing your hair there will be a period when you can't yet tie it up, but - depending on your specifics - it may not lend itself to sensible arrangement, and you may end up looking like crazy person for a few months. Figure out a stop-gap measure beforehand. I don't know - a headband or something. Some sort of a hat is good, but you might not want to wear it everywhere. Maybe some hair product for styling. Myself, I couldn't come up with anything that wouldn't itself look crazy on me, so the crazy person look it was.
- You can't comb this shit. Get a hairbrush. Something delicate enough not to irritate your scalp, as you'll be using it a lot.
- You'll suddenly start noticing hair everywhere. It's not that you'll be losing more (maybe a bit, due to all that brushing and general pulling), but what used to be few centimetres long will now be at least a few times longer. Make it your daily routine to brush at least once, so that you can collect all the loose hair at once instead of randomly leaving it everywhere during the day. Or losing it when you shower - clogging the drain can be an issue.
- You can sleep with your hair tied up. You probably should, too, so as to prevent excessive tangling. Heck, you may even be able to wash it tied up.
- I tried using conditioners, but it felt like too much of a hassle for too little gain. But YMMV. I prefer just water most days, with shampoo every now and then. I find the natural lubrication kinda works with long hair (with short hair it just looks greasy). If your scalp is often itchy or dandruff-prone, skipping shampoo might not be an option.
- Once your hair is long enough to be tied up, always carry an emergency tie with you. They will break every now and then so it's good to have a peace of mind.