Just remember, if there s something really important that you forgot, chances are you can buy it wherever you re going to be. Do bring deodorant. That's one thing most countries just don't get right. Realise that if you need people to help you with your bags, you are not a real backpacker. Realise that if your bag weighs more than you do that you are not a real backpacker.
Organisation is key.
Pack all your undies together, your pants together, your shirts together, your toiletries together etc. Be neat and organised and know where everything is. Nothing is more frustrating than having to buy more of something that you know is somewhere in your black hole of a bag, but you just can't find it without dumping out the whole bag. After you pack everything you think you need, look at it again, and go through and take as much out as you can. Ask the experts.