Since gold is limited to 150-200 per game you can opt for one of the 2 strategies:
1.) Use the gold to level up your player level and increase the number of champions you can play. For this to work you will have to spend the gold as fast as you get it and only buy cheap champions (1 or 2 gold each) combined to a max lvl 2. This way you can easily get to lvl 8 before other players and have up to 2 more champions in play then they do. If you can also get the Pirate skill activated you will be able to max your player lvl (max is lvl 9).
2.) Use the gold to refresh the champions and try to make them lvl 3. For this to work you have to start refreshing as soon a round 3 or 4, and keep on refreshing as much as possible, it will limit your player lvl to 7 and your will fight most battle with 1 less champion then your adversary but once you have a lvl 3 champion you will have the advantage. Champions at lvl 3, if you also give them 2 or 3 items, are very strong and they can easily kill 2 or 3 heroes lvl 2. This is a very risky strategy since is based mostly on luck, you can spend all your gold on refreshes and still not be able to get 1 champion to lvl 3 since the number of champions is limited and most players buy all the champions they can thus taking the champions you need.
Things to remember:
When the game starts there are about 20 of each of the white champions (1 gold) in play and 10 of the yellow ones (2 gold) and as the games progresses the blue ones are added (3 gold), no more then 10 each, and the purple ones (4 gold), around 3 at a time, and finally the gold ones (5 gold), one at a time.
The most op champs are the gold ones they can change the game, a lvl 1 karthus with 2 good items on him can kill the entire enemy team. The purple ones are very good too and if you're lucky you can get them to lvl 2 so it's a good idea considering changing your team in late game.
The best skills to unlock are: Glacial + Ranger, Assassins + Void or Ninja, Imperial + Assassins or Ranger, Guardian + Glacial or Sorcerers.
As items go, drop rate is allover the place, in the first 3 rounds you can get form 1 to 6 items, and until the end of the game you can expect to have 4 to 7 upgraded items.
For items, i would like to see an Auction House where players could bid (with gold) on a selection of items (each with a minimum bid), the items would be limited and should change once every 4-5 rounds. An alternative could be an item store, each items may cost from 5 to 10 gold thus limiting the number of items you can buy and increase the strategies you can use in a game.