You can get the most coins early (around 300-400 per minute) if you have Rusty Fan/Propeller gliders. So Get Rusty Fan fast.

Don't spend diamonds until you have fifty Diamonds. Then buy Omega Book. No other thing is required to buy for diamonds to complete the game.

Get 23,000 Coins (by using Rusty Fan/Propeller. Easiest way.) Buy Omega Glider.

After you get it, make sure that you have a Home Made Missile and some sledge (I had Bobsleigh). If you want, you may try to get better Puppet(but since you go for 1,000 height and 10,000 Length you won't hit much obstacles)

Now start and try to reach thousand height by flying up and down. If you get there you can easily go to the end of the game. After that you can try to get all other achievements and items.