Making sure that the schedule is realistic is important.  How will you know?  If you plan things properly, you will have gathered all the information you need ahead of time to create a realistic picture of the timeline.  One good way to find out is to run it by the folks in the field.  In this case, your subcontractors. Give them a little say and it will go a long way.

Scope of work.

Make sure there is enough time in the schedule to actually complete the work at hand.  If there are complicated areas within the plans, be sure to allocate time to slow down and get it right.  Measure the overall job scope against the time given to accomplish the task.

Hidden promises.

Clear these up right away.  They will not serve anyone well.  If the subcontractors believe they are responsible for extra items not in the contract, it will likely impact their approach to the overall job.  Be clear with your communication, as I always say.

Time frame vs. budget.

How do the labor costs measure up to the time frame?  This is best considered this way:  if the timeline is short and yet a lot of work is expected to get done in that timeline, you will need more labor to get it done.  Is that money in the budget?

Time frame for each segment.

Like the last idea, is there enough time in each trade segment so that subcontractors don’t start to work on top of each other due to running over schedule? Subcontractors who have to fight for space in the house, will not be happy with you and the work can suffer as a result.