Having a good idea of what a your project scope is the best way to ensure that everything gets done. This means thinking about features of the project and how these would fit into a pipeline, and what needs to be completed first.
There are two main methods of working on a project, which both depend on what needs to be done in a project, so knowing the scope is important to deciding on how to proceed. The first is Agile, which is when testing is frequent, and there's more communication between customers, developers, managers and testers. The second is Waterfall, which is when a project can only move forward linearly, which means that a phase has to be completed before anything else moves.
The advantages of Agile are that the quality of the product is assured due to constant iteration and testing. It also focuses on the client's wishes, and has the client heavily involved in the process to ensure that everything is up to standard. However, for small projects this method won't be useful, as everything could most likely be made easier if things progressed linearly. The project can easily get out of hand if things in Agile aren't managed properly as well. This means that although its a more inclusive way of working, it's sometimes easier to work in a linear way without jumping from one task to another.
The advantages of Waterfall are that it's an easy model to manage, as each step has to be completed to move into the next. This method also has a faster delivery on a project, and the process is easy to document. However, it's not good for bigger projects, as progressing linearly could hold the project back. It's also very hard to make changes to something in a previous phase, meaning any changes or mistakes will consume a lot of time to fix. The testing process only starts after development, meaning mistakes could find their way through. Correcting these would not only be time consuming but also expensive.
All in all, Agile is better for large projects with a possibility for frequent changes, Waterfall is better for small projects with defined elements.
There is also SCRUM, which is a process of Agile methodology. Scrum is a way of communicating with a group frequently, which is a great way to update and be updated on any changes taking place in the project. It's easy to implement, as Scrum meetings can be short and quick, which won't disrupt work in the group. It's a highly flexible way of discussing and revaluating a project if needed.