How to befriend my new pet rat?

Food, food, and more food! Rats LOVE food and will tame down quickly with food rewards.
A bit of peanut butter on a bite of bread or a piece of fruit like watermelon or apple will have him coming out of his hut in no time. Reward him with treats when he is gentle, talk to him and in no time he’ll be waiting for you when he hears you come into the room. Rats are very intelligent and positive rewards always work woth most animals, including us. lol

I agree with @Coloma.
Most people I know with pet rats, carry their rats with them in their pockets for hours on end.

My friend has a rat. Every time I came over with sticky/greasy/salty hands he would bite me. Sometimes my hands were just salty from me being sweaty, but most of the time it was because I had some kind of food residue on them.

I got into the habit of washing my hands, before AND after handling him, and now he only bites when I haven’t seen him for a while.

HOWEVER! I had a dwarf hamster for about 3 years. He always bit me no matter what. :(
So I guess it depends on the rodent. Good luck!

I had a pet white rat. We got to be very good friends. I had a huge play area set up for him. Food treats and more food treats were the way to his heart. Once we’d bonded with that method, he was fine playing games and enjoying company, and never bit.

Take a look at this for some pointers on Brown Rat socialization.