Here are 2 good videos that show 2 different ways to do the "Improved" or "stronger" soft shackle. Both have the ends of the rope buried. This will keep the knot from inverting and coming apart.
The first one uses locked brummel end loops and is easier to tie.
The other video is a different way of burrying the ends.
You do not have to buy a fid. I made mi e out of stainless tig welding rod. Coat hanger works too. I will dig them out of the shed later and take pics.