If you wish to play competitively on Runescape, and aim for a decent spot in the high scores and are just starting out, your probably too late. It would probably take 5-10 years to overtake the best players, unless your lucky and they choose to quit. Aiming for top player from lvl 3 now would be pointless, but if you still wish to try, by all means go ahead.
Aside from these people, these tips will help you skill faster than your peers, gain levels in the least amount of time, and generally waste less time.
Firstly, you should never waste time. Talking to friends is okay, helping them do a quest like sheep shearer is not. It's probably best not to hold their hand through the beginnings of Runescape, as it is better for them to find out themselves. Written advice is effect, going over there and helping is not. You should not leave your training spot if you can avoid it.
Increase your Runescape hours. If you have chores to do at home, or perhaps homework, get it done - and fast. Doing homework in front of the TV will distract you and deduct from your Runescape time. We all hate homework, and we all hate chores, but set your mind to finishing it and you won't waste time being distracted by other things.
Know how much your time is worth to you: If you can get 500k/hour then it's more effective for you to buy the lobsters to cook then to fish them for yourself. Some methods are more fun than others, but you must take the fastest way. If you continue to take the ineffective methods for training you will fall behind your true potential.