As the most of crafts the felting is a very time consuming hobby and there is a very little you could do to make it easier. And still! If you felt purely for hobby reason you can skip this post straight away. If you, like myself, not only make but sell sometimes and know about pre-fair frenzy and shortage of time - you may find it useful.
At first I pinpoint the part of felting process which is the most tiresome or annoying. It could be very individual, some felters do not enjoy rolling, but rolling is fine with me because I usually listen to some book or workshop on youtube while rolling. My weakest points are preparing everything at the beginning (and putting everything back!) and laying the wool.
For large fairs I need to make a lot of small items, very often in the same design but slightly individual still. I prefer to layout a few in one go because it saves me time on preparation and on choosing and getting out the boxes with the colours needed and so on. I can lay out a few items in the same design, say, with poppies - glasses cases, Kindle covers, tea cosies and so on. They are all different in pictures and scales but I use the same colours and similar compositions. I prefer to do the layouts one day and the felting the next day or even after whenever I have a few spare hours. One very intense and messy day of layout and felting and finishing later.
The same with scarves, especially if they are of medium size - I can lay out two one day and then roll them together in one roll the next day. It will not save me a huge amount of time, but it will reduce the mess and give me more flexibility with my time.
Of course it doesn't work for a large one off pieces when I need to focus on it entirely.
As an example - I was working on pictures (they are relatively small) and laid out some small items in the similar design:
