When it comes to giving consequences, I think it's important to find your kid's lever, and use it. By their "lever" I mean whatever moves them —it could be time with their friends, their electronics, karate lessons, dance class, use of the car, etc. So in giving them more of a sense of connection (getting them to come to the table for family dinner) or more encouragement for independence (doing their own homework), what lever will you use When my husband and I wanted our kids to do their college applications without our hocking them, we told them, We don't want to see you at the computer until at least one application is done. When that application was in the mail, they got the computer again for a few days. Then we told them we weren't going to see them on the computer again until the next one was done, etc. (Obviously, this requires you to keep their computer in a room where you can see it. Parents who wouldn't dream of putting a TV in their kid's room will put a computer in there— please don't, it's the same thing, and potentially even more of a time-suck.)
Money is always a great lever. When our children first started announcing that they couldn't find something (usually in conjunction with needing to get out the door on a deadline), our response was always, If I come up there and find your [sweater, shoes, CD, iPod, phone, books, sports equipment- WHATEVER], you'll pay me a quarter. (Obviously, our kids are older— I think you would need a buck now, or maybe $5, to have any impact whatsoever!) When the mom-and-dad X-ray vision thing comes with a price, your kids will no longer invoke it with the same regularity (if at all). And you'll get out the door on time, with less aggravation.
Food works, too. We had a chore list for the children every day (just written on a legal pad, left in the middle of the kitchen island), and they started procrastinating later and later in doing their chores each day until it became a frustrating back-and-forth of When are you going to vacuum the family room? Later, I have homework, accompanied by the sound of the vacuum going at 11 pm while we were trying to sleep (my husband gets up at 5 am for work). Finally, we told the kids, New rule – you don't sit down for dinner until your chores are done. In addition to being pretty funny to see the explosion of commotion in the house at the moment we made the announcement that dinner would be on the table in 15 minutes (vacuum going, sinks being scrubbed, recycling being hauled out to the curbside, leaves raked and bagged), those things actually got done. Without our saying anything else, or repeating ourselves six times on a daily basis. You can't have positive interactions with your kids if you're arguing with them all the time, or if you don't respect them – and the way to avoid that is to tailor your consequences to what's important to them, and then enforce those consequences.
SO WHAT'S YOUR KID'S LEVER (And PS, if you use the lever and nothing happens, you've picked the wrong lever. Keep trying!!)