Close your eyes, spin around, point, and wherever your finger lands on the list of possibilities is what you do. Then spend the next week agonizing that you can’t do the other thing before actually doing the thing you “decided” to do. If people don’t like it, tell them it’s their fault.

… Works for me.
(joking of course… occasionally I can make a decision, having mars conjunct my ascendant and all.)

i think about how _important_ a decision is to me. how attached i am to particular choices. if i don’t value it, i don’t care, and it can go any which way, but if it’s something essential, or moderately important, i’m going to lean on it more heavily.

which helps prevent letting otehrs walk all over you without being a bitch. but the trick is to be able to get a good sense of what you value and what you need. without that, it’s impossible. so that’s where i usually get hung up in decision making.

i have a couple aries/libra oppositions…

I have a stellium in Libra and I pretty much do what wyrdling suggests.
If it’s not that big a deal to me, I let others handle it how they will (what others want). If it’s moderately important to me, I’ll make a decision or give an opinion with wiggle room (compromise). And if it’s truly important I’ll spend hours, days, or weeks thinking about it and figure out what I would ideally like, if I’ll compromise and how, and what I will not accept (what I want).
It seems to work out for me at least 80% of the time and might be closer to 90% — I rarely feel railroaded or taken advantage of, nor do I feel overwhelmed by making extraneous decisions.