One of the first things you can do when it comes to prioritizing ideas is to sort them out.
To do this you can follow a technic that academics and smart people like to call affinity sorting, mapping or diagramming.
Let's have a bit of a serious moment with a description from Wikipedia
The affinity diagram is a business tool used to organize ideas and data. It is one of the Seven Management and Planning Tools. People have been grouping data into groups based on natural relationships for thousands of years; however, the term affinity diagram was devised by Jiro Kawakita in the 1960s and is sometimes referred to as the KJ Method. — Wikipedia
Yeah, in normal human terms, the goal is to sort stuff by categories that feel natural to the group. That's it.
If you are working with sticky notes put next to each others ideas that are in the similar category. When ideas are exactly the same stack them on top of each other with a slight margin (as shown in the picture). This allows you to see where there is already a lot of interest about an idea in the group.
When to do this?
This type of sorting can help you realize that as a group you have a lot of ideas that are about technology, but non that use the human workforce as a resource. As a facilitator this can help you motivate people to find more ideas in areas where the potential isn't fully explored yet.
Therefore, the sorting and mapping process is something that I recommend you do a few times in the middle of the ideation process and don't wait only until the end to do it.
Basics of Ideation for Innovation (Alpha version)
A future course teaching ideation theory and methods.