OK Annalise here's my 2 cents
Personally I love some worship now and then. I like to feel like like the girl really enjoys it and wants to tease/give pleasure. The robotic bobbing/hand pumping to get it over with quick is a total turn off. If I want to get off mechanically and quickly I can do that myself.
Keep in mind you've got a guy in a pretty vulnerable state, so making me at ease is a big plus. Massaging/stroking stomach/thighs, kissing around area before starting is nice. Eye contact, smiling or giggling lifts the mood and gives the impression you want to show a good time.
Just as you would be a little self concious with someone going down on you, it's the same for the guy - Hopefully everyone is hygenic so you can make you you are not acting like the whole thing disgusts you!
Whether to go covered or not is really up to the SP I think. While bare always feels the nicest and most direct, there are risks for both and to each their own here...
The more spit/lube the better and it's gotta be cleaned up anyway so don't worry about making a mess.
As for actual technique, every girl I have ever been with has the basic moves down, but has their own personal style. I think this is because there is no BJ school. I would love to meet a certified, qualified, phd in BJ. I think BJhunter is also on this quest
Please don't ignore the boys, they are tender but love to be held, cupped, licked etc. There is a spot below the scrotum (maybe connected to the prostate?) that if massaged/pressed while coming is great. There was this one girl I used to know with great breasts and she would rub her breasts on my boys while giving a BJ... Simply awesome.
Try and lookup a few tips online or in print. One I found which I generally agree with and might consider printing and handing to the next lady I see is an article called How to Give a Blowjob Like a Pro by Ann Andriani - All Sex Guide. Check it in google.
Thanks for asking!