I do know a few people whom have hired a web developer or a company to develop their prized application for web and mobile. I have heard so much of those horror stories working with web development firms, that I thought I can shed some light to prevent that from happening. Well atleast reducing the chances of it.
You need to know what you want to built. Its really not possible for a layman to know exactly the technology or the best practices to employ to get certain things done, however what every customer needs to know, is whats going on in your application. As much as I qualify the customer, now this is where you can also assess if your preferred web development firm has a clue as to what they are about to develop.
Dont feel a tad bit shy to ask them or perhaps even get them to repeat to you exactly whats going on with your application. The features, the content, the functionality, the experience of the application and so on. Given this scenario, you can understand the capability, their domain knowledge on the given application requirements and perhaps even judge if they are able to handle your project.
Personally, I would recommend choosing a web development firm who understands the business first than the technology behind it. So what do I mean? The one who understands my business will be highly likely to know what is required for my application to stand out and perhaps do what the application is ought to do, they will be able to suggest and recommend instead of just taking instructions from me to develop the application.
A big part of what huge digital agencies do is to perform fact finding, user study, feasibility study and user experience for their customers. These steps play a major role in the success of the application, however it will cost a bomb to hire one of those agencies.
Its hard work, but rewarding to find web development firms who employ a set of practices in the way they approach development of applications. Some firms follow the user experience and fact finding processes without charging you a bomb, just because they dont have the mammoth overheads that huge agencies have to deal with. Find them ! www.jankosoft.com
Keep a clear document of the scope of work and check with the firm you work with regularly on meeting deadlines. Its common for firms to verbally mention that the work is completed, do insist to test them on a test server if available to ensure if its really done.
Some web development firms are also very anal about sticking to their scope of work document, that in the event if you feel that you may need to rework the flow of your application, they throw a fit and tell you it cant be done. Do include comments on the scope of work document on those features that you think its likely for some change to happen or if you are unsure, so that both the firm and you can solve it amicably.
Working with a web development firm is not exactly transactional, like that of a Hypermart. You need to feel comfortable with the project manager or the point of contact of that firm. Developing an application can be a joy, or a pain with this one factor alone. Its sad to hear how some customers drop their projects due to stiff rules and restrictions these firms practices, once things turn ugly, its going to start getting expensive with legal enforcements. So its really worth it to spend the effort to source for the right firm to work on your next project. Hope this information helps