Open up finding out if your enemy are good or bad if he is good or playing mordekaiser or rumble (They are good counters to gp)then play defensive last hitting with your q and try to gank mid if you fail to gank mid you can use your ulti as a help for getting assist on other lanes with that little amount of gold can help your hard fight vs the good enemy.
If its a bad player without teleport then try to waste his flash when he is hunting you then you only need to go back teleport to a ward ulti and then you got a kill...
If he got teleport its alot more advanced to get kills because then you might need to kill him when he got 100% hp but in later game he dosent got spells like ghost

When you gank mid its actully kinda easy you can ask them to place a ward you can teleport to or just use you speed to outo attacking (The last one is hard if the enemy got flash) but you realy need to think about your lane when you gank you can save your ulti to it your ulti will destroy the enemys push easly and give you alot of minion kills when you are in early teamfights its important to... ks yes ks you need the gold ALOT because its nice to have warmogs but you got no damage only 120 or something thats no realy help but with the next 2300 gold you get 200 attack damage and its very nice so yes try to finish them off with your q or something

Jungling as gp is easy just start at wolfes then blue then wrath red and then double golems after that you can try to gank top/bot if not you can go back to wrathes, wolfes and then back if it possiple then give blue to the ap mid and red to ad carry or top ganking is easy just before going in use your e to buff your team mates and you then q the selected target and burst it down :)