I am essentially a by the book Stohlman style stitcher - its where/how I learned first - with different projects I will vary little things like grooving or scribing a line - overstitch wheel or irons - I will also sometimes also purposefully make the stiches lie straight (sometimes by accident!!) rather than the classic angled saddle stich just because I think it matches the project better.
I don't have the most expensive awl(s) but am certainly looking - I sharpen often, strop always and have stitched thin to thick.
In addition to the tips above (no pun intended) I will sometimes wet the really thick leather edge a little to soften but no so much as it gets deformed by the stitching process AND I always have a bees wax plug in a hole in my horse and pony clamp arms and stick the awl in to it ever few stitches - helps the awl and the needles - a Stohlman trick as usual.
Keep at it, experiment and find what works best for you. AND don't give up.