Use Parrrley to get the last hit on minions for the extra gold. Some tactics include: 1) The Double Minion Wave. You get into the enemy base and draw two minion waves towards you for 2x gold. 2) The Long Range. Use your Cannon Barrage to hit large minion waves that are far from you

All credit goes to Chugachugchugchug (http://www.youtube.com/watch?v=5-SfsRFf7Vw) for this guide's idea :)

*Disclaimer*
This isn't a serious build, it's one to have fun with. Enjoy!