I currently have a reading vocabulary of around 150 Chinese characters and probably around twice that many words. This is a pretty small number compared to what I'd need to be able to read something in a more general context, but it's enough to read a menu [see footnote].
As I've mentioned before, I've been using Anki to ensure that I don't forget previously-learned characters/words. It works pretty well in that it keeps track of how long it is since it last tested me on a given character, and tries to figure out the best time to test me on it again. However, a few months after I started using it, it gave me an alarming message — one of my characters had been "identified as a leech" and had been "suspended"!
Turns out, what this means is that I kept getting that character wrong, so Anki had decided I was spending a disproportionate amount of time on it and I'd be better off giving up on it for now. This was actually a reasonable assessment for it to make — the character was 房 (fáng), which basically means "house" or "room", and the only reason I'd added it to my vocab list was that it was in the name of a restaurant I'd come across very early on in my learning process, and I thought I may as well stick it in there just in case it turned out to be something I'd come across frequently in the future. It didn't.
However, there are some characters that may not appear very often on menus, but are still useful to know. The way I finally succeeded in learning these characters was to actively seek out names of dishes that included them, and add those dishes to my "Chinese dishes" Anki deck. The more contexts I saw them in, the easier it became to remember them.
I suppose my Anki decks deserve a digression of their own. I have three main ones — Chinese characters/words, Chinese dishes, and easily-confused character pairs. Regarding the dishes deck, I don't indiscriminately add every dish on every new menu I come across — I mainly add dishes if I already know all or most of the characters, or if it's a dish I particularly enjoyed or particularly want to try, or if it's a very common dish. However, I do relax this rule in the case mentioned above — that is, if I can use the dish to help cement a particular character in my head without adding too much of an unnecessary burden (e.g. if there are other "difficult" characters in the dish, it's not going to help).
Footnote:  When I say I can read a menu, I don't mean in the sense of being able to positively identify each and every dish on a menu I've never seen before — I often can't even do this on non-Chinese menus, as proved in the pub last weekend when I had to use my phone to Google for "agnolotti". I mean in the sense of being able to understand enough of it to order an interesting, varied, and well-balanced meal, and to pick out dishes that I've been meaning to try, rather than panicking and just picking the first thing I recognise.