Time is money, money is time.
Planning and Budgeting is crucial to a successful renovation. A great deal of time spent on research is the invaluable and will save you renovation time, money and headaches in the long run.
Research should start with what you are looking for in design and function; then what material and labor you will need to achieve your goal. For example when renovating a bathroom what functions are important to you? Do you prefer showers to baths, in which case you may want a steam shower over a bathtub. In any event you want to choose and price every component that is required for a renovation before you start.
I started by going to several showrooms and design centers for ideas. If I saw something I liked I took a picture with my phone camera and jotted down the make and model number so I can look for the best price online.
For my master bathroom I went with a walk in shower with multiple showerheads so I had to choose:
Shower body and trim
Sink and faucet
Lighting (recessed/over medicine cabinet)
Door and knobs
This is a long list and there are many choices to choose from out there. It will take time and patience to get what you want at the price you want. You will need to do this for every room you are renovating.