1. Do Your Homework. Have a clear picture of what you want. Look at magazines, take notes, visit model homes, talk with friends, etc. Home improvement projects often require numerous decisions such as floor type/size/color, location/type of light fixtures, outlets and switches, tile height/grout color, paint colors, style/height of trim, etc.
2. Hire an Architect. Once you know what you want, hire an architect. Plans should indicate existing conditions and proposed changes; sections, details, elevations; specifications on materials to be used, etc. The more detailed and specific the architect's plans, the fewer decisions you will have to make. In addition, this will enable the general contractor to give a more complete bid. Make sure the architect is aware of your budget.
Note: When allotting your construction budget, allow for the minor possibility of unforeseen costs resulting from defects or other conditions hidden behind walls or underneath floors, i.e. mold, rot, faulty wiring, etc. that would need to be fixed or brought up to code. The architect and contractor are not responsible for what they could not see.
3. Contact Building Department. You or your architect should confirm with the local building department or your building management that the proposed changes will be permitted and verify if a permit will be necessary. Usually you will need to submit a set of plans with the proposed changes.
4. Get Pricing. Once your plans have been finalized, you should submit them to at least two general contractors for pricing. Make sure the bids are detailed and inclusive. Ask the general contractor to meet with you to review the bid and answer any questions you may have.