Having said that, I often find myself vacillating upon such trivial matters as what to have for lunch!

Firstly, thank you this discussion:) Decisive, indeciseve. Both of them are useful for us(langauge learners). 

So, I  decide really easily. Do not think it is a gift, sometimes I hurt myself but undoubtedly it helped me a lot sometimes. Making a decision is a responsible phenomenon. As I see the best way what you can do is not allow to your emotion controlling you. So do not make a decision in an important thing when you are angry, sad, too happy, too frustrated, and too tired(!). 

It is not good if you hesitate a lot because it burns a loooot of energy. Think, Analyze and Decide. You will not decide in a right way always but it is much better not to make decisions if it is neccessary.

Personally, I should improve  lot in this area:) Really good topic which was connected to langauge learning. Appreciate.

I make decisions slowly but surely. I'm not impulsive and I don't just to do things right away- I normally think of the consequences of my decisions, but I can be quick at making decisions under time pressure or when there's an emergency or uncalled for situation

I'm very decisive once I'm convinced about something, and it's impossible to change my mind once I'm sure about something