Working on a responsive website where we have decided to make all content available on mobile but prioritise journeys we have identified as being key. What ways can I prioritise these journeys is it that I put those in the main navigation then possibly have a 'more' button that expands the menu to show the rest of the site? What is a good way of doing this?
It really depends on the goals of the site. In general, user journeys may be different, but the funnel should lead to as few outputs as possible. Most of my projects are marketing ones and in these cases the highest priority is to lead the user to purchasing the product. However, even this can be achieved in several ways. E.g. you have an audio system we want the user to buy. You should construct the funnels so that the user journeys lead to for example:
Now, as the main goal for the website (from client's perspective) is to increase sales, to prioritize them you will need statistical data. Which of the outputs have best performance regarding the sales? Once you have this data, you should facilitate and streamline the selected ones.
After that you can (and should) run tests on user journeys as well, to identify potential problems for users getting where you want them to get. There can be various obstacles, both functional ones, wording, graphics, etc. to eliminate.
Regardless of if the site is responsive or not it should be based upon two key things:
The scenarios for mobile and desktop users often are superficially different but the core needs and aines often remain the same.