Take your time to complete the design, so that the buildings end user,(you) are satisfied with the results, meaning it works as you want it too.
Take into consideration, things that need to coordinate together, plan for future use, ( ie; extra unused conduit in the slab, drain pipe or what have you - once its poured.... too late )
There is already some great information posted, just remember, "inspect your expect" size matters, locations of things matters, what is most important - prioritize etc. Take all things, large and small details into consideration.
Think about fasteners, hardware, and how those things work, say for example you erect a block wall, you want to mount something on that wall using expansion bolts, you will want to locate the fasteners in advance, so the cells of the block are filled, making a good connection, things like this are often over looked. Power is another one for example, locate what you need where you need it in advance, make sure you have a large enough service, receptacles, switches are where needed etc., do all these things systematically for each trade, from the site work to the finishes, checking off each so you know your design is complete, and coordinated. Nothing is perfect, so you do the best you can to eliminate problems up front, it minimizes things to a tolerance you can live with.
Once you have the design, have it drafted to reflect exactly what you want built, stuctural coordinated with architectural and M. E. P. (mechanical, electrical and plumbing items). If necessary, also have CSI specifications included, combine all pertinent information into " contract documents" so that when you ask for bids by your contractors, what you give them is complete and more than sufficiently detailed, so that the price reflects the building you want constructed. The contractors scope of work is defined beyond any doubt, also have a change to contract clause in case you need to change or add/delete something, often times this requires unit prices, alternates etc. contractors make good money on these items, so to be fair, it is important especially if you will be your own GC ( general contractor ) as you mention subcontracting major portions of work, in addition to what you will do in house.
Payments, never pay up front... period, use AIA percentage of completion method and hold 10% retainage on all contracts til the building is complete, and you have accepted the work. This gives you leverage in case something goes wrong or work is unacceptable, basically you pay monthly based on acceptable work in place, til the job is done and punchlist of any defects, incomplete or similar things are resolved.
Always maintain a presence when contractors are on site.
Again, take your time, do your research, make sure your design is complete, contains all information, satisfies your needs for the use of the building, these simple things are important and can help avoid major problems, delays and poorly done work.
Weather is always a factor, start at the onset of good weather, or leave enough time to be closed before winter so you can do the finishes inside, and not fight the elements. Timing and scheduling a building project regardless of size is always contingent on weather, play it smart, also a very good idea to create a construction schedule and include it in your contract documents so contractors realize you are serious about deadlines.
Well this is a bit different from what others posted but it is industry standard for large construction projects, even on the small scale, most if not all applies just the same.
