tldr (actually, it's quite short and worth reading) - practice sub-verbally as much as you can. If you see a cat, you think "there's a cat" in your head.
2 advantages I think this has:
1) It's good practice.
2) You will find holes in your vocabulary, and that that will encourage you to fill them.
This. Subverbal thinking IS the switch. When you start to think in a language, or even dream in a language, that's when you know the switch has flipped.
When I was living in Spain I definitely started dreaming in Spanish (it's weird to describe... ) and I know foreign friends of mine have shared similar experiences where they started dreaming in English in the US.
Haven't flipped the switch on my Portuguese yet, but I'm trying..
2 advantages I think this has:
1) It's good practice.
2) You will find holes in your vocabulary, and that that will encourage you to fill them.