Just add in moderation. Adding alcohol will often throw off the bitterness/maltiness/alcohol balance that was intended in the original recipe.
Something like a 8% ABV Hefewiezen/Lager/Amber/Blonde/Kolsch, etc. just doesn't make any sense because they typically don't have enough bitterness and maltiness to mask that much alcohol.
With a little forethought, proportionally increasing the grain and hops in a given recipe is a much better way to add alcohol than tossing in random simple sugars.
Adding simple sugars is basically the same thing as adding a few shots of grain alcohol. If you wouldn't pour grain alcohol right into your brew, you probably shouldn't be adding simple sugars just to bump ABV.
Primary #1 - Midnight Ryeder (Midnight Wheat and Rye)
Primary #2 - Florida Weiss
Primary #3 - Kane-DOH APA (Honey Citra APA)
Secondary #1 - Downtown Flanders Brown (brewed August 2012)
Keg #1 - Raspberry Florida Weiss
Keg #2 - Cinnamon Raisin Cider
Keg #3 - NONE!
Bottled - NONE!