Bull nice job all around - and if I may - like the old Army recruiting motto my advice to any student I've ever had is be all YOU can be, rather than comparing oneself to me....
As for holding a ruler snug on veg/bark tan leather when cutting or tooling - I dampen the surface well first with water - not sopping wet, but just damp - a cheap spray bottle works good or use a sponge.
The ruler, whether metal or plastic will "stick" to the leather when you add a bit of pressure while cutting or tooling straight lines. I've used cork and tape before, but found the water trick works best for me.
It works especially well when making really long straight cuts such as when getting that first straight edge on a full length side of leather which are often 5' or more long. I use a 6' x 1" x 1/8" galvanized strip of steel from the hardware store to make such long cuts - cheap and last a long time.