I like @Kilisi's answer a lot, but felt it was a bit abstract. Eradicant, I've been a contractor for a really long time and have found that a simple description of each project and the technologies used provide for a great CV (aka Sales Brochure)
Here's an actual example from my own CV (looks better in MS Word; Client and project names have been changed):
UK Life Insurance Services Limited, 05/01/2017 – 30/08/2017
(3 month contract, Renewals)
Position : Senior Developer
Repackaged UKLIS Quote, Results, and Apply functionality into reusable templates and modules, to allow rapid delivery of Life Insurance journey websites and WepAPI. These were made available to the developers as reusable, extendable Visual Studio project templates and Nuget packages.
Complementary VS project templates provided complete unit tests for the website, and custom Item Templates to encapsulate the multiple elements for a “screen” were also provided.
Implemented and improved data caching, which mainly uses wrappers around .Net MemoryCache. This has vastly reduced the load on the database servers, reducing the workload by 1 billion transactions/week (approx 20%), resulting in projected annual savings to the client of around £50k in AWS hosting fees. Further improvements have yet to be deployed and benchmarked, but are likely to yield additional similar savings.
Redesign of Quote Engines used to request quotes from multiple insurance providers which are then aggregated by the website. The existing legacy systems had been written ~15 years previously in VB6 and, over time, changes to the business have meant that the original design was causing significant performance issues. The rewrite provided a highly scalable, fault tolerant, event driven message based system, built on an nServiceBus asynchronous publish / subscribe architecture. C#, nServiceBus, Reactive Extensions, SignalR, Sockets, MSMQ, SQL Service Broker.
Technologies: SQL Server, ASP.Net MVC, C#, Jquery, Knockout.js, Bootstrap, CSS, HTML5.
Most listings are slightly shorter than this, and I only have the current position ("Current Contract") and the last five or so years worth ("Previous Work"), followed by a table listing Client / Position / Dates. I have a complete full-format list of these in a much longer CV which I also take to interviews or email when asked for more info.