first time bj...HELP PLEASE!!!

so my man and i have been together for a while but i still have never actually given a bj in my life (one bad experience) and i wanna try it for his bday...any beginners tips to help me not seem like a dummy or anything that will calm me down at all? i really care about him and want to try to get the first time over with (and hopefully well, might i add) because the nerves are just getting worse the more i wait. i just mentally need to understand what i'm doing before i can mentally be able to give it a go :-)