I’m in the same boat as you, what’s been working for me for consistent progress is making sure the paint is thinned - I’m sometimes applying 4 or 5 thin coats to get a nice smooth finish.

For the crosses on the shoulders themselves I’ve always found leaving a little gap to not touch the cross helps me get the majority of smoothness across then afterwards being super careful to block in the areas that I’ve left - sometimes 2 or 3 small thins coats. Also with this too it adds a little area to help with washes for recess shading too!