Blowjob help

I have been with my boyfriend for 2.5 years and I have NEVER given a blowjob. I know it's something he wants me to do but I'm so nervous. I also know that he wouldn't judge me or make fun of me but I can't get over my fear. I need first time tips. How to start. How to surprise him. He's not a super sexual guy. But I want to get over my fear for him. 
I'm 22 years old and so embarrassed about it.