Well, never had a rat, but from what I'm told... Be patient (;
And now, for a quote!
"Give them some time to get used to you
Rats are very social and need to know where they stand in the pecking order. They also need to know where you fit in. If you play the role of a gentle, bigger, older rat, they will respect you and also become very affectionate toward you. When you begin to spend more time with your rats, allow them to run around near you in a place where they can't hide from you, but where they have enough room to get away from you if they get scared. Beds, bathroom floors, hallways, etc. are good for this. When you pick up your rat to take them to where you want to play, give your rats a chance to climb on you by themselves. Some rats love to climb anything and will willingly zoom up to your shoulder. If they refuse to have anything to do with you, you can pick them up by grabbing them firmly behind the front legs with one hand and supporting their back legs with the other hand. Cradle them against your body or allow them to climb up to your shoulder from that position. Most rats hate to be picked up, but won't mind sitting on your shoulders or being held in your arms.
The first few times you have your rats out to play, they will probably not want to have much to do with you. This is because they are still unsure of who you are and where you fit in. The best way to get through this stage fairly quickly is to ignore them right back. Sit on your bed or floor with them running around and read a book. Bring a box of yummy cereal or healthy snacks and read and eat while ignoring them. Soon they'll decide they want to interact with you. You'll know you've been accepted as a friend when they start climbing all over you and asking for treats. Some other signs of acceptance are: hearing them brux at you, having them try to take food from your mouth or climbing up your shoulders and checking out your ears. If they mark you with little droplets of urine, you'll know you are at least considered a safe place to be - flattering, huh?"
A very big quote o.o