The quickest non-cheating way to reach level 21 is to choose the "Gold Fever" mission every time and then be sure to click on the chests on the side (I didn't even find out this was possible until I was already level 20). The game scales but badly, and at low levels this won't make a huge impact but don't worry the items you can buy here aren't of great value.

The items you want to work towards are:

God Mode Helmet - 15000 Gold (Makes you invincible)

Munchkin's Sword - 35000 Gold (Doubles XP and gold earned)

Neither item is available until level 20, so buy what you want until then but I recommend having the gold ready once you reach level 20.

I would recommend putting your points into Power/Run and Attack there are limited improvements to these with gear and once you get the helmet you are invincible so health and armour don't matter so much.

That's it for the honest folks, and I'm sorry to say that it will still take ages but once you reach level 20 you can speed things up this way. I only realised most of this by the time it was too late to make too much of a difference.

Now if you would like to cheat it is easy enough to do.

Find the local game files and find the below folder:
Doodle Kingdom\data\data\rpg

Find the file in the folder called database.xml and open in the text editor of your choice (notepad works just fine)

There are a few things you can change to speed up the levelling and gold earning process.

To increase the XP earned on a quest find this line:
Once you have found the line you can change the xp earned as you can see I have here: xp="10000".

To increase the gold awarded from each chest find this section of code:
I'd suggest using the find feature of notepad or whatever and search for rpg/items/dk_coins.ps as this only occurs once in the file.
Now same as before you can just change the number associated with "value" in order to change the amount of gold dropped.

It is worth noting that both of these changes just change the base value of each and will scale up with level.

If things are still taking too long for you and you want to unlock some goodies faster so you can spent all your free money quickly, you can change when items in the shop unlock to what ever level you would like.

To unlock "God Mode" helmet:



To unlock the "Munchkin's Sword" its the same process as above but search for sword10 to find the section of code.

If you can't win with these changes then I'm sorry I can't help you.

Cheers from Oz