By now, you should have your land or know what you are looking for. Hopefully you are aware of the land use by-laws pertaining to your area.
The next step is to produce a floor plan. You could do a rough drawing only, and hire a draftsman or architect to do the rest, but if you are like me, You will want to be hands on for everything.
If you are doing detailed drawings, then a good first step is to purchase computer program. There are many good home design products on the market. They range from expensive architectural tools to open source drawing programs. Some are easy and intuitive to use. Others are complicated and require considerable study or training. My own preferred choice is a low-cost home design program that is easy to use. I spent about 100 dollars. Check the reviews before you buy and if possible, use free trial copies. Never give your credit card number to obtain a free copy.
Many home design programs have catalogues of home furnishings and appliances. You can incorporate these into your plan to see how things fit. measurements of the items can be modified to match your actual choices. Most will also generate a materials list. I have found these to be of little value because of regional cost differences and construction standards.
There are many other features to these programs that you may, or may not use, but exterior and interior views can save you from straining your imagination.
Placement of windows and doors are important. They can be important visual feature of your home. Strive for balance, both inside and out. The front of your house, the side facing the street, is the one most seen and deserves the most attention. It is likely the first thing you will see whenever you come home as well. It should be attractive and welcoming. Well planned landscaping, however, can enhance any facade. Do not neglect a pleasing view.
If you are placing many windows on the south of your house, consider the solar gain, a good thing in winter but not so for summer. On a single story house, this can be alleviated by placing the windows a little higher and providing 24 inch or more for eaves. At least at higher latitudes. Landscaping with deciduous shade trees to the south can also help considerably. A low E coating for your window glass is almost a must, no matter what side the windows are on.
I cold climates, try to avoid large, north facing windows. Even the best windows have poor thermal properties. On the north side of your house the temperature differential is the greatest and therefore subject to the greatest heat loss.
You must have one exterior door, but most houses provide more than one. They should be placed for convenience, and for easy escape routes in an emergency. They should be at least 32 inches wide. One door 36 inches wide, or more, is a good idea for ease of moving furniture and appliances in and out. It should provide straight in access. A visually appealing door can add a lot to the front of a house.
Don’t forget security. If possible place doors and windows so they are visible from the street or at least from the neighbors. Higher windows provide less easy access to criminals.
Consider resale value. You may think you will live there forever, and you might, but people’s lives and circumstances change. There is no point building more than you need or want simply for resale value. It is, however, a good idea to build so that a house is easily expandable. It might even be you, that needs more space in the future. Try to place windows and doors where they will work for expansion. A window 40 inches, or more, wide is easily converted to a hallway entrance and the header is already there if needed. Think of how heating and cooling can be provided. Use trusses for the roof structure so interior walls can be easily moved or removed. I have seen a few 3 bedroom homes that have been converted to 1 bedroom when the kids are grown and gone. There is usually a developed basement to accommodate guests.
Today most people like to have a deck or patio for outdoor living. normally the best location for a deck is on the East where you have morning sun and the house provides afternoon shade. North may be better in hot climates. If you have other sources of shade,you can utilize that. A deck should have easy access from the kitchen or dining area. It is a big help when entertaining or dining outdoors. Plan for a natural gas hook-up for a BBQ if NG is available in your area. If you can build your deck within a year or two you may be able to avoid the cost of extra permits by including it in your house plan and site plan.
Garages are almost a necessity in cold or hot climates. It is not necessary to heat or cool them to the same degree as your house. They actually save energy over idling your vehicle to heat or cool it. They also protect the finishes and interior of your car from sun damage. An attached garage is very convenient and protects you from the weather as well. If it is outside your budget right away, design so it is an easy addition.
Think of the environment. Net zero energy homes are possible, almost anywhere. The capital cost will be greater but operating cost will be much lower. Especially on a larger house. A smaller house, however can be extremely efficient without spending much extra.