I'm sure we all have had this happen more times than we care to admit. How many times have you loaded up to go riding only to find when you're gearing up that you forgot something? Even if you're not the one it happens to and your buddy forgets something like his gloves, boots, goggles, helmet or whatever it's a crappy way to mess up a otherwise good time.
The best way to avoid not having all your gear together and ready to go is get a large gear bag and use it. Get one that's big enough to hold all the gear you need to go riding and keep it packed and ready to go at all times. That way when you get the call to go moto, or just hit the trails, that parts done. You most likely don't wait to decide to go riding before you get your bike ready. Why do that with your gear? Gear bags that are big enough to hold everything don't have to be cost prohibitive to own. Sure there's some deluxe ones out there that cost over a hundred bucks, but to me that's more than I want to spend. If you look around, you'll see that a nice big bag can be had for less than $40.00. I got one on sale at a local dealer 4 years ago for $29.95 and it has been used a lot and still is holding up great. Seperate compartments for the boots is definately the way to go.
Every time I come back from riding I wash the gear that needs washing and repack the bag and set it next to my bike. If you do this and make it a habit you'll thank yourself many times over. Especially when your buddy forgets his gloves and you have yours. Who knows, maybe you'll have an extra pair stashed in there he can use cause you know he just tends to forget things.