Spray Painted Surface Very Rough -- Follow-up

I posted a message about this quite a year ago. The problem was that
the spray paint from cans seemed to have high pressure that bounced
the paint off from the inside of a book case. Recently I had a chance
to add another "book case" like small cabinet in my house. This time
I fixed the problem that I mentioned in my previous message by spray-
painting each component of the cabinet before assembling it together.
I needed to keep paint off the areas that I needed to glue by covering
those areas with blue tape. This works well and I likely will
continue using this approach for any future projects.

The other alternative that someone has suggested previously is to use
paint sprayer that I can adjust and lower the pressure. But I don't
have such an equipment (always want to have one; but cannot justify
the purchase). Therefore, I am still spraying paint from a can.

I post this just in case someone gets into the same problem and wants
to know how this should be fixed.

Jay Chan