Top ten modeling mistakes architects make:
1.) Alignment - This is uber important. Especially when using the model for IES, CFD or other analytical tools. Floors connect to walls, parapets extend past roof lines, footings align with slabs or are integral to them. Oh yeah and windows and doors need to be modeled as constructed. Unfortunately a 500 lb aluminum storefront window can't bear on only the substrate and exterior finishes.
2.) No generic modeling. Or at least don't share the models until they have material and intelligence otherwise the models are distributing maybes and kind ofs which don't help any body and in reality can really confuse the team.
3.) Model as constructed. Walls are not 150 ft tall. Floors are not 1700 ft long without joints. Pre-cast panels are just that, panels. Also when concrete floors and deck pans are modeled they need to be modeled to their exact dimensions. Also ceilings have wire supports, which can easily be worked around pipes for the most part, however pipe hangers, duct hangers and other supporting appurtenances need to be modeled. Use best judgement.
4.) Don't use design options. A lot of tools will not recognize the difference between design option 1 or 2 when exported and lump everything together. Separate files work here and in reality work better at an early stage.
5.) Align and orient all structure to grid lines and exact locked and constrained dimensions. This saves on time (moving a grid line as opposed to 100 columns) and makes the modeling inherently more accurate.
6.) If a floor replicates exactly a number of times use groups and copy. You can always ungroup if the program becomes more complex.
7.) Don't model the structure if you have a structural engineer on the team who is doing BIM. The engineer's model is what should be built and tested, not the architects. Link it in, save time and if you need additional structure create a separate workset that you can send to the engineer to update his model.
8.) Limit 2D info. BIM is nice in the fact you can click on a component and it will tell the user what it is and that you can model as needed.
9.) Control your levels and families. Family creation needs to be created as accurately as possible and with flexible sizing options. This is the only time I encourage an architect to use a generic block and then go back later and change it to a worthwhile family object. Also learn how to model families correctly, these are often the biggest propagator for "blank" clashes. Levels need to be limited. When there are too many different objects hosted to too many differing levels it will get very confusing during the analysis phase unless there is some system put in place that makes sense to the team.
10.) Don't send junk. if the model isn't finished, if it's not usable and if it's not coherent it won't be to anyone else.