Play in what position you want to play in.
You will enjoy your football much more this way, and the more you enjoy it, the more likely you are to go out and practice on your own accord and improve.
I play as a striker, and got offered a contract with my local team Luton Town, who are semi-pro, so I'd like to think I know a bit.In terms of actual tips for being a striker, it can be quite complicated depending on what level you play and what style of play your team decide to use. I'll start with the essentials.
Biggest thing with any position is your control. It's stressed a lot, and this is for good reason. You can have the best shooting ability on the pitch, but if you cannot get receive the ball and get it under control, you cannot shoot. To practice this, my favourite drill is to just throw the ball in the air and then control it in one touch. As you improve you can make it harder by throwing/kicking the ball higher, and doing it in a restricted area, such as a 5 metre square, which you must stay in. Once you've mastered that you can implement a control and turn into it, and then a control/turn touch and then shot on goal. It's not practiced enough as it is such a basic and easy drill, but you can score a lot of goals by being able to control and turn to goal in one touch, and finish with the next. You should also practice kick-ups, to improve your foot-eye co-ordination. This will improve all aspects of your game.
Next thing is shooting. As a striker, your primary job in the team is to score. If you cannot shoot well then you will never be a great striker. This all comes down to technique. Leg strength is something that will come as you become an adult, and begin strength training. You can be the strongest player in your country, but poor technique will cause you to have an average shot at best. There are various guides dotted around this forum.
In terms of power and accuracy, I always felt accuracy is over stressed and power under stressed. Sure you need to be accurate enough to hit the target, but I used to miss a lot of chances because I wouldn't put enough power into my shots, especially during one on ones with the keeper. This led to them often getting saved, regardless of the fact that they were all going straight to the corners. As soon as I started using more power, I started to score a lot more, as the keeper had no time to react, and often even if I was inaccurate, the goalkeeper would often fail to deal with the power.
Next is physical ability. This is what I meant by it depending on what style your team plays. I remember playing in a horrible team that would always lump the ball forwards, in 4-4-2. Yeah, standard English side with no tactics. But it worked, I was the speedy striker who could run onto loose balls and dribble past players, my strike partner was older, stronger and bigger, and although less mobile, could bully players off the ball as our team mates lumped it to him. Of course having speed and strength is always a bonus, but not always possible if you're quite light like I am. Best advice I can give is to play to your advantages.
Best of luck.