I transitioned into web development. Because I had no relevant experience, I accepted a 4-month internship in a company, with the aim of getting tenured. (It was made clear from the beginning by the company that this internship was a way to test me prior offering a permanent position).
I didn't negotiated my internship wages (see previous question). I like my current job and I am keen to stay. I know they would like it too. (I am pre-registered for a company training that is after the end of my internship.)
However, I want a significant raise (more than twice my current salary) to match what I think I'm worth. (I already received offers in this range — cf. previous question.) I know this means that I must accept to leave the company if we don't find a common ground.
I'm two months into the internship. Let's assume they'll make me an offer.
Besides doing the best job I can, I am wondering:
What could I do now to have a better hand when negotiating my salary when being given tenure?