I always thought the best thing you could really do is get to know your profs really well. I try hard to do that every semester. I sit in the front row so they would recognize me, and I go into their office hours and ask them questions. Or you could just ask them questions before class or after class that carry more weight than "Wait, will gauche be on the test?". I avoid after class questions because usually there is a long line to see the prof. Introduce yourself, say "Hi, my name is Hindiana Jones, and I was wondering about blah blag blah" When I go to their office hours after I am done asking questions directly related to class I ask them about topics related to the subject material but not directly related. For instances, I asked my history of film prof about Star Wars, just because I was curious about what she though. I asked my cell biology professor about her research, because why not. I found to be what she was doing kind of borning, but she knows who I am, knows my name, and knows I am proactive enough to go get my questions anwsered. The better they know you the better LOR they can write. Having them write "This student got an A in my class" isn't very helpful. Professors are people too.Some may be rude, or nonresponsive, but you can use your judgement on that. You don't have to be buddy buddy with every single one, but you should try. Going in the day before a major paper is due or a major paper is about to happen makes it transparent that all you care about is the grade. Thats just my opinion.
