We lay our clothes out on Sundays as well--ea. outfit (everything from socks to hairbows) is folded into a leveled hanger in my toddler's closet. She has a chore chart (picture-based w/ velcro-backed 'done' markers) as well as a Time to Teach clock (turns green when she can get out of bed & is the start time of her chore work). As soon as she gets up, she goes potty, makes her bed, puts her lovey away, gets dressed and then comes down to eat breakfast. After that, 1 more potty trip, grab school stuff (backpack, lunch bag, show & tell, books, etc.) and straight to the car.
Toys stay away, TV stays off.
We wake up earlier than I'd like, but it keeps the stress level WAY down, as it gives us some wiggle room if my daughter's slower than usual (or has a struggle w/ the closure on her clothes, or wants to eat a lot for breakfast).
My daughter is pretty cooperative, so I'm lucky in that sense, but in the rare moments where she refused to get dressed (insisted she couldn't get her socks on herself...even though she's been doing it for 2 years) or dilly-dallied, when it was time to leave, we left as-is. She only had to go to school half in her jammies & without eating much breakfast once ;)
Just set your schedule (even an actual schedule on the wall: http://www.lakeshorelearning.com/seo/ca|searchResults~~p|... 'cept with 'get dressed', 'breakfast', 'brush teeth', 'gather supplies', etc. on it. ) so they can see how close they are to 'go time'. It'll really help them to develop a sense of time & to know that it's important to be on time. Allow plenty of time to get where you're going (without having a casual 'Go ahead and take all day' schedule) and be consistent.
Kids crave routine & predictability. They'll fall into line quickly if you stick to it!