First blue sky it as to what you would like to have involved in the home automation system. Make a long list and talk it over with the installer. Perhaps things will have to go or be modified, but it is much easier to add before installation than afterward. What appliances do you want to have in the system? Is security an issue with you and how can that be incorporated in the system? Will you want to access you system when you are not at home? If so, how about internet access to your system? What is not all that necessary or useful? A good home system installer will be adaptable to your needs and even make suggestions you may not have even thought of but would love to have. Better to include them now.
As each option is added, the price tag goes up accordingly. Be aware that many systems you wish to control are already equipped. Ceiling fans, blinds and lights can be purchased with their own remotes. The proliferation of remotes and subsystems may make this impractical, but it is one less expensive way to control your home environment with less fuss.
However, the temptation might be to automate until you drop. Be sensible and put into the systems tasks that you need to do every day like locking the front door, turning out the lights or turning on the TV. Too much of a good thing can make for overcomplicated and stressful living.