Building Starcraft 2 Maps

This time the subject matter is of a, to me, rather different nature. I recently started to dabble in the art of making competetive Starcraft 2 maps and wanted to share some of my failures with you.
My first map was of a horribly wrong scale and contained an unbalanced amount of resources.

Here are the rules for resources:

• The fixed amount of starting resources are 8 minerals and 2 vespene geysers.
• A normal expansion contains 6-8 minerals and 2 vespene geysers.
• A golden expansion contains 6 rich minerals and 2 vespene geysers.
• Rich vespene is never used

Map sizes (effective):

1v1 : ~120x120
2v2 : ~150x150
3v3 : ~170x170
4v4 : ~190x190

Map expansion count:

1v1 : 3~4 / player
2v2 : 2~3 / player
3v3 : 2~3 / player
4v4 : 2 / player

The grid system uses 8 units for a big grid square (G) and 4 for a small (g).

Building rules:

• Start locations should be contained on a at least 14 G² (/ player) big plateu.
• Expansions should have ~6 G² empty space around it.
• A number of Xel'Naga towers (1-4) can be placed around central positions.
• LOS (Line Of Sight) blockers should be placed around key locations (e.g. so that micro unit controls can be used more effectively.
• A fun level has one/several central point(s) to battle over.