First off, don't use a phone camera. It looks...weird and you're not getting a good picture of your body because you have one hand on the phone. Get an actual camera and set the timer.
Second, flattering lighting is a big plus and probably the most used. I use it EXTENSIVELY. It's the ONLY reason why any of my pictures look half way decent. Over head lighting and up to the side (therefore, simulating a V effect on your chest.) are the best because they cast shadows where you need them most. Early morning lighting is my favorite just don't go crazy like I do with my contrast.
And of course, take them after you worked out your most pathetic looking part since it'll be a veiny and have some blood going through it. For me, thats any part of my body so any day suffices.
Suck in your gut and flex up your chest and arms. Nobody will be looking at your face so feel free to make weird faces.
(and yes, I agree that professional photos are a little narcissistic - your body might be super attractive but you standing around posing or laying down in the sand or on some rocks really isn't - real men here!)