>The problem is that these jobs rarely ever conform to the original time estimate.

For your next project estimate the entire project and break down every component (form, report...) and write it down. Keep track of exactly how long it takes for each component. Do this for a few projects. You will then learn what you underestimation factor is and can adjust future bids accordingly.

> Communication is often very bad on the clients end, since they are either slow in answering my questions or send me incomplete or inaccurate descriptions of what they really want.

Create a spec document. User must sign off on it. Every change must be accompanied with a change req and a revision to the time and cost.

>Considering human nature, It will probably always be an ongoing battle to get the information I need from clients.

If you use the above, they will be motivated because money will be on the line.