hello from MI!
I used to be the same as you. I went to a homebuilding and renovating show a few years back and there were a few courses on how to choose colour schemes and how to make different colour schemes work.
After that, everything was easy and we found we could create some spectacular effects by keeping to one very simple rule:
Choose three colours that work well together. They can compliment or contrast, it doesn't matter.
Use two of them as main colours, and the third as a highlight colour and then use them throughout the room - walls, ceilings, floor coverings, fabrics, and so on. You don't have to have three main colours all as paints - you may paint or paper the room in two colours and then use the third colour in furnishings, for example. Or paint the walls one colour and use carpet for your second main colour. However you do it, you'll find the three colour rule works well.
A little bit of experimentation and you'll find it can work extremely well. From my own experience, I have found that the two main colours ought to compliment each other, but the third can be quite a bold contrast if you want.
I would recommend going to a local bookstore and having a browse through their home interior design and decorating books. Look for some inspiration. Look for something with lots of handy hints that explain how the profesionals get the effect they want. Incidentally, when you're looking at the photographs in these books you'll notice the three colour rule appearing time and time again.
Finally, when you're experimenting, start with a small room - an upstairs bedroom or a bathroom for example. Then by the time you're on your main rooms you'll be getting great results every time.