A lot of people I know have recently turned 18 this year (including myself) and I wish I could just shake them and say "what are you doing". Not every situation is the same but, for the most part...you should get working on these things.
1. Writing down all of your information.
Scan your debit cards, print out a list of your passwords, save it onto your phone, etc. It's 2018, you shouldn't have to do the whole "forgot my password" thing every time you try to log in somewhere or have to call your mom at the bank saying "What's my account number again?".
2. Deep cleaning your space.
You're probably moving out soon so it's time to start deep cleaning your room/ space at least once a month. Use a Clorox wipe and stop living with five pounds of dust on your vanity.
3. Locking your personal belongings.
Getting a lock box is a major key. This is where you can keep all of your documents, paid bills, social security card, etc because we can't keep calling mom and dad every time we're filling out a job application to ask them what our social security number is. (I highly recommend memorizing that number though because it makes life ten times easier.) If it is important to you or has value, lock it.
4. Thinking about retirement.
I know what you're thinking.. "Really Emma, that is like 50ish years away"... and you are right but, the more you save for retirement, the more you can do during retirement. That is the time where you should be on the beach or going to the movies everyday. I know a lot of adults that don't know when they can ever retire because they did not think this through ahead of time. Be smart and save up.
5. Have a checking, savings and emergency credit card.
If you haven't done this yet, I literally don't know what you're waiting for. This is your wake up call.
6. Building credit.
If you plan on moving out of your parent's house anytime soon, you should probably start building credit. All you have to do is be 18 and pay off your bills each month, monitor your score, and be smart about what you're doing.
7. Budgeting.
This is so important. You need to start budgeting what you do with your money each month by saying "Okay I just got paid. This much needs to go in my savings, this much in my checking and I can only spend things amount of money on myself". This will get you into the healthy practice of not spending all of your paycheck on restaurants, movies, concerts, etc.
8. Having a life game plan started.
This will obviously change throughout your life because things happen but you should probably start thinking about what you want in life, what your values are, life goals, etc. You can never be too prepared.
9. Not going crazy with all of the things you can do now.
Just because you can have all of your favorite store's credit cards...does not mean you should always use it. Yeah, that 20% off is cool at first but it's not so cool when you can't afford to pay off the bill. This also applies to going too crazy at sex shops, smoke shops, gambling...keep yourself in check.
10. Don't forget to chase your dreams.
Go to school, go to your dream job, travel. Do whatever as long as it is what you really want to do. Make your life the way you want it to be and work towards your goals.
I know I haven't lived a lot of life yet but, these are tips I have heard from family members, teachers, just from watching others and saying "Yeah I don't want to be like them". I hope people my age start doing these things soon to better prepare themselves for life.