Earning $1mil is not the easiest feat. The first suggestion I'd give would be to sell a month subscription. My normal price for them is about $1.2mil. But I know that not all players can pay for things online.
Otherwise... Here are some tips!
- Do quests -- Quest will earn you a TON of money. Some are quick, some are slow. But they all pay off in the end. Especially when you can mine on Pirate, collect shards on Lava, and collect the various items from Cloud to sell. Not to mention the awards you get for making 25%, 50%, 75%, and 100%!
- Go gem hunting -- Comb every step of the beaches on various isles (especially Tail, Cat, Desert, and some of the smaller isles to the east of Horse Isle).
- Mine on Pirate -- What I do is I get about 50 gold ore, 5 diamonds, 30+ rubies, and 25 or so emeralds. I make four gold necklaces in Whiskerton, then sell everything on Rock Isle. You can make about $60k or more from one trip like that.
- Collect shards on Lava -- Visit some of the dragons and collect as many shards as possible. Then sell them on Rock Isle for a hefty sum!
- Collect the items from Cloud -- Peppermints, silver linings, and moon beams are very rare on HorseIsle. They are needed for quests, so some people would be willing to pay you quite a bit for them! And if nobody needs them, you can sell them in stores for a very nice amount of money.
Those are probably the best ways to make money quickly. Making necklaces sort of ties in with gem hunting. So another suggestion would be to make as many diamond necklaces as you can, without buying any of the diamonds or gold ore!