Ask as many questions as you like
I usually try to add at leat 15 keywords, usually ends up more like 40
exifer is a great tool, it allows you to create templates, which mean you dont have to re-enter all the keywords foa series of similar images..
once there uploaded - providing the sites are intelligent enough (most are) all you have to do is categorize your images and wait for review.
It feels like a long wait when you submit your first batch
Doug