It's so important to move in when the time feels right for the both of you. Not because of financial reasons, your roommate just moved out etc.
TALK ABOUT YOUR CHORES
A lot of arguments happen because someone needs to take out the trash and do the dish. Communicate who does what to avoid any unnecessary disagreements.
MOST IMPORTANTLY...COMMUNICATE!
Don't wait until it's too late. Don't bottle up your feelings. Communicate before it's gets to be something.
MAKE TIME FOR YOURSELF
Continue hanging out with your friends, going out and running errands, doing hobbies. It's important to maintain your own sense of individuality.
DECORATIONS
Stick with neutral colors and decorate together. Make it a fun thing for both of you guys to do together.