A steel ruler is really useful with an exacto knife to cut straight lines. I also use different colored pens to go over the lines of the folds to ensure that they will fold perfect. I use red pen for the concave folds and black pen for the peak folds, its been really helpful for me at least.Ok I have my folds and lining up perfect in that case. My accidental use of printing paper was actually good practice for folding and aligning everything. I’m going to finish cutting out everything I had cut out before hand and then tomorrow pick up some tacky glue.