how?

You can't but if if open with d4, it will happen often enough.

Won't happen! For example, against me, if you play 1.d4 and 2.c4, you'll wind up in a Dutch.

I've been testing 2.Bg4 against the Queens gambit for year's now, with success. It's better than the "Baltic Defence" 2.Bf5.

Won many games with it, now I'm actually getting better from drug dependence. It effected my game play, but I'll continue to be back up to 1800/1900 in a year hopefully.

This will not happen, but if you want to allow the QGA without any QGD lines maybe some reti line allows for it: 1. Nf3 d5 2. c4 dxc4 3. e3 Nf6 4. Bxc4 e6 5. d4

But there are no shortcuts. Not playing the usual move order may avoid slav and QGD theory, but it allows for many other possibilities from black also.