Which to start with? Which do you think you'd enjoy more?
If all else fails, make a list of all your ideas, number them, then take little scraps of paper & put the numbers in the paper, dump it all in a bag, shake & pick one. I'm serious here. Do something to force yourself into it.
Once you have an idea, this is my favorite method to outline a plot:http://hollylisle.com/fm/Workshops/n..._plotting.html
I really cannot say enough about how much I love notecarding. It's what I'm using to write my novel (I am writing by hand, & carting around my little collection of cards). It is so
versatile. I've rearranged my notecards more times than I can count to make the plot flow better. I know of no easier, more flexible way to get down the bones. (Of course, you don't have
to come up with an outline...but I think some sort of structure is incredibly necessary for those of us who have one idea after another jumping out of our subconsciousnesses!)
This is another method I really like the idea of, though it didn't work out for me:http://www.advancedfictionwriting.com/art/snowflake.php