There are several factors that you need to carefully consider before selecting the firm that can best deliver your project.
Capabilities - The contractor should ideally have in house architecture and structure resources for delivering your design. They should also possess in house project management experts whom are experienced in developing a detailed project plan and effectively orchestrating the build process. All these capabilities will be active during the build project to ensure that the project is delivered with the utmost quality and within time, scope, and budget.
Experience - You must ensure that the contractor has the necessary architectural, structural, and delivery experience for delivering a quality structure within time, budget, and scope. Be mindful of contractors who quote very competitive prices but are not able to deliver within the three tenants of project management (cost, scope, time).
Cost - Most clients consider this a significant variable in selecting the contractor. However, there are many contractors in the market where they provide very competitive pricing but they are not able to meet the expenditure requirements during the project. Ensure that the contractor uses the appropriate market research methodologies and costing models for providing you with the overall cost of the project.