I deal solely with electrical subcontractors and I believe that the biggest mistake competent electrical estimators make is to properly educate clients and potential customers on what actually wins projects. I tell my customers that I do not have the magic bullet that is going to win them projects. I tell them about what my award percentages was during good times and what they are now that the economy has turned sour. I feel that I need to also inform them of things such as chasing projects that are posted over the internet in their market that their odds are even less of winning the project. A lot of my clients are not very business savvy so I explain to them that their labor rates and O&P margins will greatly affect their win percentage. Many do not even understand basics of overhead.
I believe the more information the client has going into the relationship the higher the odds are of a successful and sustained relationship. It is when I fail to properly articulate things such as what I mentioned above that the client gets discouraged and may either elect to use another estimator or simply quit outsourcing their work!