Either resisting and airbrushing takes time and practice,dont kick your self to hard have patience and practice practice you will get there,mask looks good,look at different drawings and what not and work on your shading
These holster i make for my self are trial and error i experiment with dye,antique gels,hi lighters,etc...as for the quick draw holster i kinda wanted the pic to stand out thats why i left it lighter around the pic