Don't you just love it: you're playing bot lane, minding your own business and not feeding. You feel confident: hey... I think we can win this!
Then you see it... the top lane giant who just storms into the lane and eradicates everything in his way because your top laner decided to roam, rather than focus him and now the enemy top laner is 50+ CS ahead, and you know... it's over.
If you want to be THAT top laner, then you will need to split push. We can tell you how, but do you also know who the best split pushing champions are?