Take a ball everywhere you go. You go town with a mate? Take a ball. Barbecue with the fam? Take a ball. Walking the dog? Take two balls. Play with it all the time, passing will be second nature. If you're a winger, kick it too. Kick it high, then catch it. Don't be afraid to drop it ever, have the confidence to stick your hands out and catch it, rather than catch with the goddamn forearms like so many seem to do. Practice enough now and it'll be second nature.
ALWAYS go to training, always. No matter how crap it is, it's rugby and at your young age you should fit in as much as possible. Its all reps. Reps reps reps. Reps mean muscle memory, and that means being able to carry out the task without the slightest bit of thought. Remember when you were learning how to ride a bike? Tricky? Fall off? Now you can jump on and peddle away without worrying about falling to the floor and dying (it happens, bro).
Same goes for tackling and the contact area. Get as much practice in as possible. That moment just before the person you're meant to be tackling hits you, a blanket of fear comes over you and causes you to either tackle them high or stand off and get unbalanced. It usually results in a missed tackle or being boshed onto your ass. At the very least you'll concede metres. Precious metres that the best of them seldom do concede. If it helps, think of something that provokes an emotional reaction from you, something that makes you angry might work, causing you to lunge into them with your shoulder. Everyone loves a winger who can tackle. For example, a few years ago I realised the 100th anniversary of world war one was coming up. The image of men, British soldiers, running over their own trenches to almost certain death randomly popped into my head during a contact training session. Whats one 'brave' tackle compared to such mass heroics like that? Seriously? If they could do that, I could easily do this wussy bit of contact in a damn contact sport. It might seem far, but imagery works!
Practical pathway information for a young (english?) lad like yourself would be to get into the county squad, any way you can. Get your coach to recommend you for the county, get a mate who is already in to speak with the coach to get you to a training session. County opens the pathway. From there, get in the starting team. At u16 level you will play the other counties for a chance to try out for your region. This is North, Midlands, south east and south west. Then these play eachother to get into the England squad. England u16B, A and elite. This repeats for under 18s so you potentially have three cracks at this. You may find an academy picks you up along the way, which is a better pathway than getting into the England squad because by then you will be under contract and under the eye of an established club and its player development officers.
In the end it, it comes down to hard work and perseverance. If you're good enough, it will happen eventually. Ben Morgan and Mike Ross weren't childhood stars but look at them now, established test players and big names in rugby this side of the equator. Work hard, bro.