dark colors

i wear primary dark colors like black, brown, dark green, and such. I was my clothes with cold/cold water and i use kirkland detergant (the water solid little sandy thingy) then after wards i put it in the drying in low and i put in this tissue like thingys that are called softner sheets or something and i set it to dry. so what do u think i can do differently that can help my clothes not fade color. is there some special product that i can buy?
vinegar? doesn’t that smell up the clothing?
if you don’t use dryers what the heck do u use? when i hang it outside it makes the clothing smell.