Insulation, Radiant and Vapor Barriers - new construction on 2x4 walls

Any suggestions on improving R values on new construction 2x4 external walls, attic, etc. We have a lot windows (dual-pane Milgard 3050 single hung), 2-story. Looking for tricks on improving insulation..

2X4 walls limit you to R-13 insulation. The only way you will increase that is to make the walls 2X6 so you can go to R-19. You could also add a layer of 1" foam to the outside of the studs before the siding goes on. That would add another R-5 or so. The attic is easier. Find out what the minimum amount of attic insulation reqired is for your area, and add a foot of cellulose to that. Just be careful not to block the attic ventilation in the process.