Economy management is important. In MMO’s like WoW, player skill can play a huge different in PvP. In LoL, richer teams end up slowly gaining advantage over the long run because the better equipment helps them secure domination.
Last hitting is the act of killing a minion with your attacks and spells being the lethal blow. If you can get that last hit on minions, their deaths will yield anywhere from 15 to 30+ gold. Killing a Champion nets you 300 gold. If you have been killed once, you can minimize that disadvantage by last hitting as best as you can. If you can score 30 creep kills more than your opponent, you will have neutralized their gold gain (provided they haven’t killed anyone else, either).
Every chance you get to last hit, take advantage of it!
If you’re playing a caster of sorts, you may not want to use your spells early on to secure those last hits because you may need them against your opponent. But as you progressively get stronger in both levels and item gear, you’ll be able to afford to spam spells a little more with enough reserves to get you through the next engagement. For example, I will frequently Dark Binding one unit as Morgana if I know it will get me that last little kill instead of leaving it to one of the minions.
Ideally, you want to aim for about 200 combined creep score by the 20 minute mark. Most of us starting out won’t be quite that good yet, but that’s a okay. It’s a good value to aim for.
Combined creep score – Your creep score + (Number of champions you have killed x 30). If you have a creep score of 150 and 1 champion kill, you have a combined creep score of 180.
Now get out there and practice that last hitting!