I don't know about all of you, but with five kids my van gets dirty fast. We'll go to the park and by the time we come home, the van looks as if we've been gone the WHOLE weekend!
Here is what I do to keep my van clean--at least a couple days out of each week.
1. When you get home from the park, school, church, a friend's house, etc. take everything OUT that doesn't belong. After every trip take everything out. It may take a few trips into the house--it's worth it though. I think that is what contributes to a continually messy vehicle: stuff piling up. Receipts here and there, gum wrappers, empty cracker boxes, a stray sock, etc. all contribute to the mess. This is my best piece of advice for keeping your vehicle clean.
2. EAT in your vehicle. Okay, this doesn't contribute to cleanliness, but Lee and I travel A LOT and with five kids, it would be practically impossible to not eat in our van. If you do eat in your vehicle, try not eat things that are messy, sticky, or hard to clean up. For the most part juice and pop are banned in our van (especially something red), Cheetos are a no no, and kids chewing gum (and not keeping it in their mouth) isn't a good idea either. I try to let the kids eat things like pretzels, which are easy to sweep out or vacuum up.
3. Keep a hand brush in the trunk. I have a pink hand brush in the back of my van that I use quite often to spruce up my van. Pulling out the vacuum and the extension cord take some time, not to mention vacuuming itself. I save vacuuming for the big cleaning jobs. Usually my van just needs a sweep from smashed pretzels, small rocks, bread crumbs, and stray grass and leaves. I can sweep it out in minutes and it looks great!
4. Don't be afraid of carpet cleaner. Buy a can of upholstery/carpet cleaner from the automotive section to have handy at home. We just moved a couple of weeks ago, and when I did an over-haul on the vans, the carpet cleaner made such a difference! It takes some time to scrub the carpets, but oh how nice they look when done!
5. Keep wet wipes and a microfiber cloth handy. I like to grab a couple of wet wipes to wipe down the drink consoles, dashboard, the seats (in the Honda they're leather), the floor boards, and other little nooks--like the area under the lever to recline the seat. After I get the initial dust off of the dashboard, I pull out the microfiber cloth and give it a re-wipe. (Or you could use a dampened lint-free cloth in the first place.)
Those are some main tips for having a sparkling clean vehicle. Happy cleaning! You CAN have a continually clean vehicle!