How do I know what type of soil I have?

I'm going to be planting roses soon and have asked a question regarding them in the roses section but it has brought me to this question, how do I know what type of soil I have and what makes a good soil. Can bad soil be improved or do you just have to work with what you have?

 

All soil can be improved Paterson but most soils are just fine.

Can you show us a pic of your soil - a general view and a spadeful - and we'll tell you what you've got and how you might improve it.