Diet and exercise are definitely the first keys. I had and average load through most of my 20's and then dropped quite a bit of weight...about 40 pounds...and my load became much larger. Since then I've unfortunately added 25-30 pounds back and now my loads are below average. The worst part is I just got married and the wife lets me cum in her open mouth or on her face whenever I want, so now I wish I had larger loads...I'm back to eating better and working out though, so hopefully there will be an improvement. I like the sound of the "cum on her face diet"...that's awesome.

Other than diet and exercise, prolonging the orgasm definitely builds a bigger cumshot, but unfortunately some wives (mine included) just don't have the sex drive to bring you to the brink for a couple hours, so diet and exercise are your only options.