Try do begin with some big attractions like Space Mountain or Big Thunder Mountain. Or get Fastpast tickets for them right away and go to another attraction... Peter Pan and Buzz Lightyears Laser Blast seem to be very popular as well. Do them first, or at the end of the day...
You should be able to do the Studios comfortably within 3/4 of a day but head for Crush's coaster first and get a Fastpass for Tower of Terror. These two rides build up queues like fury! As for Disneyland Park. It is well worth covering this park and trying each ride in turn. As Mikeland said, for a real treat go to Walt's for a meal. If you have time, pop inside the Disneyland Hotel above the entrance to the park - you don't have to be staying there to look around. It's main door is to your far right as you look at the front of the building. Try and get hold of a good guidebook. the "Unofficial" guide is a real good one. Most larger branches of W H Smith and Waterstones carry it.
Now I'll turn that little mouse's dream into a nightmare Fantasmic !
I personally would recommend staying within the resort (while trying to avoid Cheyanne and Santa Fay).
If you are used to WDW (which from your sig I suspect you are), then DLP will offer more subtle delights than the big flashy thrills you will be used to. My main recommendation while visiting DLP is to take your time. The details in the park offer the greatest charm of all of the parks and should be savoured.