One mistake I've made was becoming friends with people on the outside of work. Things really backfired when the best friend back-stabbed me and I have to see him and a few others every other day when they come in. Now I'm seen as the asshole. Why? Because I do every thing the way it's supposed to and they don't and I don't tolerate it. They want to make mistakes that beginners make when they are the ones who went to school for this and should know better. They want to call me out on things that's not even my job to do, but their own. Why do they single me out? Because I'm not one of them anymore.
What do I do? I come into work every day with a smile laughing and joking with everyone including the ones who don't like me. 99% of the time, they ignore me and try to hold in their laughter. I do this though because it makes the job easier. They can't see me as a threat if I'm including them in everything I do. Only if I ignore them and do my own thing. They'll see me as someone who can easily run circles around them and it makes for competition.
Keep work and life separated. As soon as you walk through the door, remove your attitude and get in a good mood. It's hard, but just do it. Get rid of the competition so none of them will perceive you as a threat. As crazy as this sounds, if you did something better than one of them, it would ruin them I'll bet and that's what they are afraid of so they don't want to show you anything. Ask them for help. It doesn't matter if you don't need help, just ask and include them in your project and give them credit for it.
At the end of the day, they are the ones feeding off of a title. If they want to take credit for something, let them. What matters most is what you know and if you know you're good, that's all that matters. However one has to wonder how good they actually are. This is where your final product showcases your skills and you will be ripped to pieces with either good or bad results. In the end if you get fired or receive bad results, you weren't good enough so you get back out there and keep at it or find something you think you may be better at. If he gives you more responsibility, that's when you really know you're getting there. Once you walk out that door, get a new attitude. You're no longer at work.