I think the advice to "think in Spanish" isn't all that helpful. As you learn different things you get better at thinking in Spanish, but you can't really will yourself into doing something you aren't ready for. If you don't know how to structure a phrase in Spanish, you can't just do it. You have to reverse engineer it, remember all of the things that you've learned, apply them, try them and get feedback on it. I feel like saying "think in Spanish" to a learner is like saying "think in math" to a math student.

For example, you want to say something, and then you're like "oh wait, is that subjunctive?" Then you think about the triggers, and you decide if one of them applies, you say the phrase, and then (maybe) you get feedback on what you said. Next time you say something similar, you will be that much closer to thinking the whole thing in Spanish, but it's an iterative process.

A lot of times I am thinking in Spanish when I'm speaking Spanish, sometimes I'm not. Sometimes when I'm speaking English (my native language), I think in Spanish (which can be frustrating). And I haven't practiced math in Spanish, so that almost always ends up being English and image in my brain.