The fact that you've had experience, even if it wasn't ideal, means that you at least have some working knowledge to go off of. Maybe try doing it with a virgin. They will naturally look up to you even if you don't have that "aggressive" personality that you want. Just take it slow with them. I find that bottoms, even if it's not their first time, are usually pretty tense, so what I do (or offer to do) is to give neck/shoulder massage. It helps relax them, and loosen up their muscles. Plus the simple act of touching creates a sense of trust and comfort with you, which will make everything run smoother. It also helps in getting clothes off, since you just start by taking their shirt off and nothing else.

Then as for the sex itself, use lots of lube. More than that. More. More!! MORE!!!!! Then double the amount of lube. Good. Now just start fingering them, one finger at a time. Then add another slowly. Once you can fit four fingers in and stretch them, they're ready.

Put your dick in starting with just the head. Once you get that far, just leave it in them. Don't thrust- let them get used to it. This can take several minutes, so be patient and assure them that they're doing great, especially if they're inexperienced. Don't push them, and don't do anything that makes you seem impatient; again, getting their trust and comfort is key to being a good top. If they ask you to pull out, do so slowly, and repeat the steps above as needed.

Once you can get past your head, slowly (and I mean VERY VERY SLOWLY) start to go in deeper, still assuring them that they're doing well, how sexy they are, etc. I find that doggy position works best for this too. Feel free to compliment them, whisper in their ear, etc. If you can make the bottom feel sexy and wanted, then they'll really want you. Keep in mind that even experienced bottoms can take a while to get to the point of actual thrusting. So just go slowly until then.

Even if all of the above seems out of character for you, just fake it until you make it. It may be weird at first but keep practicing and you'll be a total stud in no time. PM me if you have any more questions.