I went through high school as a lazy ass - didn't do most of my homework - but I'm extremely good at taking tests, so that's where I found my passing grades. I essentially rode my test scores all the way to college, down to the SAT/ACTs, which countered my (extremely) borderline 3.0 GPA. If you can do very well on the tests - I'm talking perfect scores in at least one subject, if not more than one - you don't need to do keep your GPA above a 3.2. If you're not sure, keep your GPA up there. Classes in high school are not hard, as long as you do the work. No matter what, don't let your GPA fall below a 3.0; I can tell you from experience that it sucks having to pull it out. Don't fret if you get a C or a D in a class or two though. It happens, and you'll live. Don't fret if you miss the occasional homework assignment either. It's not the end of the world. Don't stress over the work, just do it; even done half-assed is better than not done at all.
Find a good group of friends and stick with them. Doesn't matter what 'crowd' they're in, so long as they know you for you and don't care if you're a nerd or anything else; hang out with friends who are fine with you being who you are. This may sound cliche, but it's important. If you're at all musically talented (or even if you're not), get in with the band kids. They may not be your typical 'cool kids', but they'll be friends for life if they're anything like the band kids I know from literally everywhere; even in college, saying you were in the marching band will get you immediate friends who were in the marching band, even if they (or you) were only in it for a year or two. I was in it for six years, and anyone who legitimately makes fun of you for being in it isn't worth being friends with (or paying attention to) in the first place. Most in high school won't care too much, and once you get in to college people tend to love the band, especially colleges that are big on tradition. You'll always find people who are idiots and dickwads; ignore them. Seriously, just ignore them if you can. Stick with people you like, don't be afraid of who you are, and respect who others are. Just because you like something doesn't mean everyone else should too. They shouldn't think too differently of you for it, but if they don't like video games don't press it on them, and they shouldn't press their likes on you. Having said that, it's always good advice to at least try new things, whether you like it or not. That advice applies to things like hunting, video games, etc, not drugs or alcohol or sex or whatever else; that stuff is purely up to you, and I'll address it specifically later.
If you end up in a confrontation, don't run away from it. That'll only cue them in that you're an easy target. If it's verbal, deflect it with humor (and if you're quick enough, get a little comeback in, preferably one that they're too stupid to understand) and move along. If it's physical, well, I'm of the philosophy that every male needs to have his ass handed to him at least once in his life. This might just be your time. Whatever the school rules may say, don't just roll over and present your rear to them on a golden platter. Make it a bit difficult, but again, don't fight dirty; no balls shots, no eye gouging, no biting. At the very least you'll earn a bit of respect from them. Avoid it if at all possible, however - I know schools tend to be horribly strict on these sorts of things. Handle it how you will from there; if you think it's serious enough to report, do so. If you think its a one time thing and it wasn't serious, I'd (personally, mind) let it slide. I got in to quite a few fights during my high school years, and most of the guys I ended up fighting I became friends with later, because I didn't have down and I wasn't afraid to fight someone bigger than me fairly. I also didn't start the confrontations. I ended up with some bruises, a cut or two, and the occasional black eye, but also with some respect from the others and, in the end, some friends. Remember that, but don't expect it; if it happens, all the better. That said, the chances of a physical confrontation isn't very large. I'm one of the few that it happened to more than once, and most people never go through that.
Remember that teachers are there to help you. You'll find ones you like and ones you hate; the ones you hate you don't have to see after the class is over, but cooperate with them so long as it's reasonable. Be polite, but don't be afraid to speak up. If you end up with a teacher you really like, talk to them. It'll help throughout high school if you stay in contact with teachers you like; they can help you get through other classes, advise you on paths to take, give you letters of recommendation, and even give you connections for later on in life.
When it comes to alcohol/drugs, in the end it's your choice. Personally, I would avoid them both. Not like the plague; you don't have to ostracize people just because they've become binge drinkers (in fact, staying friends with them will give them support for when they need it, and you'll be there to, hopefully keep them under control). Know that, whenever you participate in those sorts of things, you run the risk of getting in to trouble with the school, your family, or the law. I'm not saying you need to avoid all that stuff, but know what you're getting in to and what the consequences will be before you do. I had a couple drinks on occasion throughout high school. I never got drunk, and I never did drugs. I was always careful to not have too much, and I was always careful to only do so at places where I knew the party or whatever wouldn't get out of hand.
Do not, DO NOT, smoke cigarettes. They don't do anything for you, at all, and they will kill you. That should be blatantly obvious, and it's stupid for you to even have one. Straight up, plain ol' stupid. It's not cool, and people will not like you for doing them.
More general things; treat girls with respect, always. If you like someone, be honest with them (ask yourself, honestly, what's the worst thing that could happen?). One of the most valuable lessons I've learned is that, often, it is better to listen than to speak. Know what you're going to say before you do, and make sure you actually listen to others; that'll let you know about them, and it'll let you make friends easier. Don't underestimate the value of a genuine smile, a slightly cocky half-smirk, a well-timed wink, a strong handshake and a hug. Smiles, handshakes, and hugs in appropriate situations are all extremely powerful. Make sure you get outside and stay in shape - trust me on that one, it's worth the extra work to have the self-confidence and the ability to move heavy things. In shape does not mean skinny, it means you should be able to work up a sweat when you want to, be able to run a mile in under 10 minutes, etc. Don't forget the difference between skinny and in shape. And have fun, because as awesome as college is, high school can be nearly as good if you do it right. It'll help going in to college to have friends going with you too.
Women... well, you'll have to figure them out on your own. But don't be afraid to talk to them, and spend time with them.
