Read King Kabuki's Heavy bag 101 thread. I also practiced individual punching technique and basic combinations a lot.
for pad work, I just did what my trainer told to throw. He would correct me on technique and stuff as we went a long. If the person holding the pads doesn't know what he's doing, then it doesn't help much.
doubtful or he would have someone helping him. thats why he is asking here. Before you even think about throwing hundred of kicks at any bag make sure you are kicking right, dont go throwing kicks liek Butterbean.
There's GOTTA be someone in your town, your school who knows how to box. Don't necessary need a certified professional trainer but after someone who's got experience gives you pointers every once in a while you can start drilling combos into the bag.
but you still have to realize the true purpose of the heavy bag Lots of people like to hit the heavy bag for "power" or because it's the most common boxing instrument they see in movies.
Truth is though, the heavy bag is also for technique and balance in stance (like, throwing a flurry of shit against this 130 pound object while doing all your pivots wihout losing your balance), and working footwork in conjunction with resistance. These things, the real purpose of the heavy bag, can't be done without an experienced trainer.
if you find someone who knows how to box you should also ask them to show you what the purpose of each type of bag is. Though your mention of kicks seems like you're interested in kickboxing, most anyone who is good at "standup" is going to have a boxing background, since it's just so crucial to have good hands.
Get the basics down before you start playing with combos and different technique. Listen to your coaches. Coaches are always busy in a good gym walking around helping people. Fighters getting ready to compete get A LOT of attention from trainers/coaches, and that takes some away from you.
The best thing you can do is ASK. You need to be able to ask someone (a coach OR an experienced person, whoever is available at that second) if you are doing something wrong OR right. When your coach gives you something to work on (like certain strikes, footwork drills, whatever) than you just work on that until he/she gives you something new to do. It's that easy. You don't want to get bored either, so in between practicing whatever they are having you work on, you can skip rope (takes a while to get good at, so use it to fill time and warm up), practice the speed bag (like skipping rope, it's not something someone can really teach you, you have to just get used to it), or whatever.
The bottom line is that a coach/trainer/partner/whatever can show you what to do, but you have to just get in and practice it. IT TAKES TIME. You will NOT have someone there standing over your shoulder the whole time. You need to know what it is you are working on, ask questions in between, and keep at it. I always have a list in my head of what I need to work on and those are the things I practice in the gym. If people are available I get them to hold mitts, pads, spar, or whatever. There are classes, but training in fighting is a very self-motivated self-driven thing.
But get your "base" down first. The worst thing is learning something wrong and having to re learn it. If you jump too far ahead you will be making a lot of mistakes. Good luck and enjoy!!!