The steps I took in creating the pants for this puppet are very similar to the way I made the shirt, but I'll go through each step just so it's easier to visualize.
First I created a fabric template out of paper.
I then pinned the template to puppet double checking the look/fit of the back and front of the pant leg.
Once I was content with that, I traced my templates onto a pair of old jeans with a chalk pencil.
I cut out the design.
I then sewed about 3/4 of the back and front section of one pant leg together (while inside out). The other top quarter that is not sewn together will later be used to join the two legs together. I also left about 1/4 of an inch at the bottom for the pants to be rolled up like you see in the final picture.
Next, I flipped the pant leg out to it's correct side and checked to see how it was fitting on the puppet. It's always a good idea to leave a little extra material on the top of the pants. That way if you need to make some slight adjustments to the length you'll be able to do it without having to cut out and sew an entirely new pant leg.
In the final step I join the two pant legs together at the top 1/4 that was previously left unstitched. Then I flipped the pants inside out to their correct side, use some hot glue to roll up the pant cuffs at the bottom and BAM! You no longer have to worry about animating a naked puppet.