use a lower oppacity when using the brush and eraser tools etc.
#Transparent colors?
neat thicket
the value field at the top (when using a painting tool) that usually is set to 255
at the very top toolbar
where you adjust the size and softness of a brush etc. too
there should be 3 value fields (if you use a brush or eraser). Hover over them for a bit to see which one is which
if you set it to 7 that means your brushes/erasers etc. will now paint/erase with an oppacity level of 7
keep in mind that paint tools are additive, not replacive