My beers never carb consistently in two weeks. Four weeks is typical, and I usually bottle condition for six weeks before I start drinking them just to get a little better consistency of carbonation and the noticeable improvement in flavor that comes with a few more weeks of conditioning. The waiting is the hardest part, as Tom Petty said, but you'll be glad you did. Be sure to drink one beer at two weeks, one at three, another at four, five, and six, and record your tasting notes so you'll get an idea how beer changes over the first few weeks.
You should condition your beer at room temperature, by the way. The yeast will have a harder time doing their job of processing the priming sugar to produce CO2 in the bottle at refrigerator temperatures. It could dramatically lengthen the time it takes for your beer to carbonate if you try to let it condition in the fridge.
As cuinrearview said, be careful of soap, and surfactants in general. Your beer glasses should be as clear as possible of any soaps or surfactants. Don't wash your beer glasses in the dishwasher if you use Jet-Dry or a similar anti-spotting wash aid. It's basically a type of soap. I have almost 40 beer glasses, and I wash them in plain dish soap and hot water, rinse them really well, and let them air dry.
The type of beer you are brewing, the residual proteins, and the amount of isohomulones from high-alpha hops all affect head formation and retention too. It's not just a matter of carbonation.
Assuming you are brewing five gallon extract batches and not mashing, you could steep two or three ounces of carapils in a grain bag at 155°F to 160°F for 20 minutes in your brewing water, then remove it and continue your normal brewing process. Carapils is a very lightly kilned crystal malt that is added to beers to increase body and head retention. Too much, and you get cloudy beer, so don't over do it. It will add unfermentable sugars to your wort so your final gravity (FG) may go up a point or two and you may notice a bit more sweetness. That's another reason not to overdo it. But a little will improve head retention in your beers.