Is this for extract, or for partial mash or all-grain?
If using mostly extract, you could try using different brands of extract to find one that ferments less than the others. There is a broad range of variability in fermentability between different brands. Another thing is, you could just plan on adding an extra pound or two of extract to every recipe, this will definitely help, plus it will jack up the alcohol a little bit.
If you are mashing at all, mash another 3-4 degrees F (2 degrees C) higher than you have in the past, or more than the recipe says. You should also calibrate your mash thermometer by measuring the temperature in ice water and boiling water, and see how far off it is. Few thermometers in the world are perfect.
As a last ditch fix that will certainly work if nothing else does, you could add a half pound of lactose or maltodextrin per 5 gallons of any recipe at all. These are non-fermentable sugars, which are not very sweet but will certainly add body and mouthfeel to any beer.
Cheers.