Using your breath is, I think, the fastest and most effective way to start aligning your body and developing body awareness. See the "breathing" archive for ideas. Some students who are really twisted up need the 6 Steps to Perfect Posture. Some don't. After the body is mostly aligned, though, everyone can warm up quickly just by gently reminding the body what to do. Here's the abbreviated warmup that I do with my students now that their bodies are alive and aligned:

1. sniff quickly and deeply into your chest, sending your chest up in the air (same as step 1 in 6 step warmup).
2. let your breath huff out.
3. Hairball (step 3) to force all of your air out.
4. open your mouth and let the air rush into your body without you making an effort; the vacuum just fills you up with air.
5. easy breath out.
6. get "thinner": suck your stomach back towards your spine. Your chest should not rise.
7. get "taller": breathe in as you suck your stomach up towards your chest, letting your torso stretch upward as you breathe in.
8. holding your breath, shrug your shoulders up and set your heels down into the floor, stretching your middle from both ends. Arch back a bit to stretch your stomach even more.
9. bend at the hips, continuing to set your heels down, stretching your back. Feel your head and neck getting longer, your head stretching taller away from your body.
10. let your breath out as your let your shoulders fall back down.
11. "hairball": expel all of your breath.
12. vacuum your breath back in by opening your mouth.
13. exhale, tossing your violin into position.

This whole operation usually takes a minute or less.