Not spending on war would be a good start.  As far as what we do spend, perhaps it would be best if we did away with robbing Peter to pay Paul.  If Peter keeps his money, he will use it to better himself and his family, as he sees fit, and in so doing better the world as a whole.  If Paul receives Peter's money, Peter's plans are delayed/destroyed to fund Paul's.   Paul is unlikely to use the resources as carefully/usefully, as he did not have to work to obtain them.  Of course, the process of robbing Peter and paying Paul is very inefficient and brings out perhaps the very worst in everyone involved and society as a whole.  A good read on this is the short story "not yours to give" by Corckett.