I dislike covers.Come up with your own 100% original compositions.
While I do enjoy and appreciate the cynicism (and, I assure you, I'm completely serious when I say that), covers can be fun. Cover bands, on the other hand, are pointless entities. But, if you're in a band that already has a handful of originals, what's wrong with taking a pre-existing song and then tweaking it a bit? Of course, that's what has to be done. I wouldn't recommend trying to completely recreate a recording, which is absolutely impossible in regards to recreating the exact same energy that makes the song great to begin with. Find your own energy and use the chemistry among your band-mates to apply to the song, and make it your own. I think the best compliment you could receive in critique to a cover is "this doesn't sound like the original." It's just a shame that people are so dense that they manage to convince themselves that that's an insult.