One thing to remember, for getting levels requirements for military buy missile interceptor batteries. They give you the most points for the least money. Dont worry about ammo, it doesnt give points.
Most people would say set your level requirements for 'peaceful mode' where military doesnt matter, at least for the first few levels.
If you have loads of military over, then sell it as soon as you can, on the world market.
The single biggest mistake that is made by new players is to try and build an army straight away, it will destroy your economy. Get making some decent money first, war is uber expensive.