1) Read widely--as in, multiple genres, not just that of your own writing.
2) Read in your genre. A lot. Everything you can get your hands on.
So which is it? I know, the answer is obvious. It's both. But when you hear these bits of advice they never seem to be paired together. More often than not, authors are told one or the other in blog posts or writing books, or simply comments by other authors. Yet, they must go hand-in-hand.
If you don't read your own genre, you won't know your competition well enough to at least keep up with them. You must keep up with current conventions as well as the history of story and style of your genre.
At the same time, if you limit yourself to reading only that genre, you may find yourself simply rewriting what's already out there (likely in overabundance). Reading outside your genre opens you up to new ideas and makes sure your writing doesn't get stale.
This translates over to finding critique partners, but it's not quite as evenly balanced on the critique side. Seeking critters outside your genre gives you fresh insight. But, here's the issue I've found--if they don't read my genre at all, they can't give me solid advice. Maybe they can help me straighten out an awkward sentence, or find typos, or let me know overall if they like what I'm writing.
But if they don't have a clue about common fantasy or horror elements, they will try to "correct" where there is no correction needed. I'm not saying their critique isn't useful, but as genre writers we must be knowledgeable about our domain, so that we know what advice to follow and what to ignore.
This goes for age labels as well. If someone has never read a single YA or teen novel, and you write YA, then I guarantee that critter will point things out to you from a solely adult-fiction-writer perspective. Again, not saying don't seek their critique, but be selective about what advice you follow.
A friend of mine once said to me after critiquing Finding Angel, "Keep the fish and throw out the bones." Great advice--but you have to be able to tell the difference first.