Running Plumbing Supply Lines

The updates are moving along and I'd like to thank everyone for the help.
I'm ready to run new supply lines to the kitchen and bath, distances are not great (10' - 15' or so). What I have now is 3/4" CPVC capped off and ready to run.
From the fixtures to the floor I have those flexible steel braided lines. I've got some shutoff valves that have a "compression" fitting for 1/2" CPVC, that would be near floor level.
When should I transition to 3/4" and how do I mount the lines? Should I use a different shutoff valve?
All my friends have old plumbing so I can't look to see how this is done.
Jeff

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Normally you would run the 3/4 hot and cold to the area and then branch off with 1/2" to each fixture. At lowes, hd, or your favorite hardware store you will find 3/4-1/2-3/4 and 3/4-1/2-1/2 T's that you can use for this. The 1/2 can come up from the floor or out of the wall depending on each specific situation. Try to avoid putting any plumbing in exterior walls, come up from the floor instead.

Hi Jeff,
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Normally, you would use 3/4" as your "main" line, then transition to 1/2" for the lines running to each fixture.
3/4" pipe is used for the main line because it allows more volume so you won't lose pressure when multiple fixtures are opened.
1/2" pipe is used for the branch lines, as that is all that is needed for a single fixture. If you were to run 3/4" all the way to the fixture, it would take forever for the extra volume of hot water to reach the fixture.
As for the shutoff valves, this is how I handled mine:
1. Connect the incoming 1/2" CPVC to a brass drop-ear "transition" elbow. This has a female CPVC fitting on the bottom you can glue to your CPVC pipe, and a female threaded fitting on the front. The brass ears allow a secure mounting to blocking in the wall so the valve doesn't wobble around, or crack any pipe. These are available at most home centers.
2. Install a short 1/2" brass pipe nipple in the transition elbow. Mine were typically 3"-4" long, depending on the wall thickness so the threaded end protrudes from the wall.
3. After the wall finish (drywall, etc.) is complete, slip a chrome trim ring over the pipe nipple.
4. Install a right angle shutoff valve with a 1/2" female thread to connect to the pipe nipple. Make sure the "outlet" side has a threaded fitting, and not a compression fitting (I think it's 3/8" thread, but it has been a few years. Just make sure the flexible hose you use will thread on properly).
5. Use flexible steel braided lines to make the final connection from the valve to the fixture.
I used the same transition elbows for all of our shutoff valves, shower head mounts, tub spout, etc. They're not cheap (5 to 8 dollars each), but make a nice transition, and provide a solid mounting for anything sticking of the wall (shutoff valve, shower head, tub spout). They may add $50-100 to your project now, but it could save you big headaches in the future.
Good luck,
Anthony