If I work directly with clients I always start with some wireframes and work in an incremental. Planning out layouts, content and so on.
After that I start designing mostly the landing page in sketch. Choosing colors, typhography and the overall mood and feel of the site.
Then I basically create a prototype in marvel with the fully designed landingpage and the wireframe subpages. The landingpage is for showing off the mood of the site and the wireframes to show of different site layouts.
Sometimes I design a second page, too to show of different elements and how they are designed. Then we come to revisions and I have only to rework 1-2 pages and the wireframes which are not that pixel perfect.
On bigger projects I really like to keep a styleguide which is insanly easy in sketch, so I can show of different UI elements and how they behave. The benefit is, that I can show of all pages of the site, without designing them pixel perfect. The client can see all components and can see the layouts as wireframes and 1-2 fully designed pages.
After the desktop version is final, I create the wireframes for the mobile (smartphone) version for some subpages which are important and have different layouts and 1 or 2 fully designed pages. Then prototyping in marvel and show it to the client. This way I can be sure that the design of the elements is final and the changes to the mobile version are most of the time pretty small.