Just remember to last hit in the start of the game, with your Q-spell. Thats why i play with clarity. If you are mid, then just last hit until lvl 6, and then you should have farmed so much, that you should have the gold to buy a "Blasting Wand". And you should also have last-hitted enough to have over 150 ap, if you also have runes. Then you should get a bit agressive, and you sohuld be able to get some kills :D