As tough and humdrum it sounds to look for e-commerce solution providers, more painstaking it is to research about them, and the more you research the more options you get.
Develop APIs to ease and accelerate the integration between various software components and technologies including payment gateways.
Resolve any issues and fix bugs actively during or after the completion of the coding and the development process as and when required.
Acquire high-quality links from other websites to your website to enable easier crawling and better search engine rankings.