M.P.
I am not very fond of the idea of home decorators. the concept is weird. if you feel you are overwhelmed by this idea of doing it totally yourself. start with 1 room and let the other go for now. what ever room is going to be used most start there. if you thinking you would want a theme to go thru the whole house. then and only then think about the whole house.
you realise if you go to the paint store or a furniture store they will have people there to help you? I used to work in a paint store and I can't tell you how many times some one would come in and we got talking about colors and what colors to put together. I am sure I saved someone lots of money with just that help. same with furniture stores and places like pier 1.
magazines and books at the library will help you.
ask your friends too for ideas they know you and know what you like.
many times if you just sit in the room quietly idea will come to you.
just think of all the money you can spend if you do not have to pay someone to do this!!! LOL