Most important thing to learn from this lesson: it's important to not only read the advice, but also to understand why certain advice is given. In your example, the recommendation is to not share salary (be it current or desired) is there to avoid getting a low offer. But if you have done research and know how much the position is worth, there's no harm at all in sharing your desired salary in that range.

And then never forget that recruiters are humans. In good companies, recruiters are actually pretty good humans. Good companies understand that giving a candidate an offer below market rate is the easiest path towards attrition issues. So they are not trying to screw you over. Twice already I have said to a different recruiters "I would accept the offer as it is, but I would highly appreciate it the numbers were a little higher" and twice I got a better offer (if you read Reddit you would think this can never ever happen). So read the people, read the company. Lots of crappy places out there, but lots of decent ones too - so don't go into conversation with hr as a battle, rather a discussion with a human being where you can learn more about company and they can learn about you.