Try out the Great Orb Project mini game and you will be given a great rewards and more RS gold.
Source: wikihow
Play the mini game and you will earn great rewards and RS gold
To be able to participate the Great Orb Project, the players need to have at least level 50 Runecrafting skill or greater and it is available at the Runecrafting Guild. You can gain experience for Runecrafting skill and at the same time you can earn more RS gold.
By selling the water talisman you got from the rewards, you can earn much more runescape gold. The water talisman can be obtained by exchanging the tokens you got from each game from token exchanger. Each water talisman is worth 50 tokens.
Every time you’re team won from each game, you will be given 1000 talismans per game as a MEMBER and 750 tokens as a FREE player. If the teams have a draw, you will be given 500 tokens per game. Once you accumulate enough tokens, you can now buy a lot of water talisman from token exchanger and re-sell them at the Grand Exchange for runescape gold.