Here's one I learned from a script writer:
Get a bunch of index cards.
Write the name and a sketch-bio of a character you find interesting and might like to use to tell a story.
You don't have to use every character in the story you'll write, this is just a "casting call" for possibles. (When cooking you don't use every spice in the rack, just the ones you need to get the right flavor.)
Write down each idea that's fizzing in your brain, one to a card. It forces you to focus.
You'll soon fill up a stack, and by having the hard copy in front of you you can shuffle them around into a usable order.
I used this during a collaboration with another writer. We had to cold-plot a book (as in anything goes, all ideas are considered).
First we figured out the characters we would need to tell the story (the girl, the guy, the bad guy, sidekicks, minions, spearcarriers).
We gave them names and a driver. A driver is what moves your character forward in life. Han Solo's driver was to make lots of money as a smuggler, but he got side-tracked into being a hero.
Every character has an agenda. When it's in conflict with the agenda of other characters that's a GOOD thing!
That in place, we decided what things needed to happen in the action-oriented story: the bad guy doing something BAD, the good guy follows the clues, the girl foiling the baddie, a few nookie scenes, background locations, etc.
Sounds cold, but once on the cards we were shuffling them all over the floor fitting them together into a plot that eventually turned into the best book we'd ever done.
It's a device that may not work for everyone, but I get like you--too many ideas to sort out! This helps me bring order to the chaos.