Caliper brakes dragging could be caused by a number of things. Some of these things, others have mentioned. But here's what I usually go through:

1. Is the front wheel centered in the fork and resting on the dropouts? If not, I loosen the front QR and press down on the stem holding the bike vertically, and retighten the QR. Then squeeze the front brake. Is it centered?

2. If centered and the calipers are still chronically dragging, I check the brake center bolt for snugness to make sure the brake is on relatively tight to the fork, and then I find a 13 or 14 or sometimes 15mm cone wrench and slide it carefully onto the center bolt flange. On older brakes, single pivot, this flange has groove cut onto the face and holds the caliper spring, and has flat sides for centering the brake. On newer dual pulls, this is a star flange with no groove. If you have an anodized brake, you may want to pull a small bit of masking tape on top before you use a metal tool to do the centering. If the entire caliper set can pivot, you can simply use the cone wrench and center the brake roughly. If too tight, loosen the brake center bolt/nut, hold the calipers centered and retighten and keep pressure on the cone wrench to prevent the calipers from pivoting while tightening. This gets the rough adjustment. For fine adjustment, there should be a 2mm allen bolt near the side pivot point on dual pivot calipers. This does the fine centering. If you've already maxed this in or out, I recommend you screw this adjuster so it's midway, and repeat the above bulk recentering procedure. Now squeeze the front and it should stay centered.

3. Okay, you went for a ride, and a few miles down the road, you're dragging again. Check the cable routing and how you've radiused the housing from the handlebars down. A chronically short or long cable or one that impacts some other protrusion on the bike (e.g. something dangling off the handlebars) can cause the cable to pull and pivot the entire brake. Brifter cables, if improperly routing can also cause abnormal brake pull and pivot the front brake out of alignment. This most often happens at stops or trying to trackstand at lights when one turns the handlebars to extreme angles not seen during normal riding or cornering. In this case, I re-route and replace/re-cut the housing and re-install the front cable.

4. If the above three things don't work, I recommend a deer/hunting camera in the garage set for infrared and motion detect. This checks for gremlins, goblins, careless dopey kids or spouses who may have a vehicle door or some other way to knock your bike near the front brake in a regular way. And this will cause the brake to go out of whack regularly. Yeah, I know the probability is low, but believe you me.... I've been there and wonder were the heck those paint chips on my front fork were coming from... As we're talking vintage, mint, Bridgestone steel bikes. Don't get me started...