A couple of points important to remember are that selling does not end at the signing of the contract and Project team members are needed to complete the selling objectives.
To me successful selling extends the typical sales cycle beyond the closing of the deal. You sign the contract; deliver what you promised (and more if you are good), get testimonials, referrals, and repeat business. This sounds easy but is not always done as a planned activity by most companies. Sure the outputs are desired but they are usually an afterthought and not part of active plans within the project execution stage. In some cases they are only done when the Sales team is reminded of the need or the project is getting ready to close.
How can you ensure you have success as a team?
First you need to have a unified approach between those who sell and those who execute. You will have a difficult time if it appears one “over-sells” during the process and one “under-delivers”. The value message must be understood by all and the how it is delivered must also be understood. The combination of the value and the work quality is important to achieve the later sales needs.
You can’t totally depend on the sales team to ask for the referrals, testimonials, and references from the client. I used to believe long ago that these roles should be kept separate and distinct. I wanted to avoid any appearance of “conflict of interest”. But getting the referrals, references, and ensuring repeat business can be handled very well by those executing the work. I believe this because of the relationship that develops during the executing of the value/work. If you are working closely on-site with the clients, educating, and demonstrating your expertise then you will have a strong and maybe better relationship than the sales team has with the clients. They have seen you deliver and learned from you so they will trust your recommendations and requests.
You should be discussing the needs to support sales internally during the entire project from kickoff to closing. All it takes is discussing the strategy with the team, defining clear deliverables, and taking action. In the end the team members delivering on the value and quality promised are your best sales tool.