Support main having difficulties in ranked

Hey there fellow summoners!

I've been experiencing some serious difficulties in ranked as of lately. I find myself currently stuck in Silver III and am having trouble getting out. I have reached promotion to Silver II multiple times(at least 5 or 6 times maybe more)and the past 3 times I reached promos I ended up losing the first 2 games every time, which is extremely frustrating. Granted I'm not the best player out there I feel like if I can make it to promos that many times I should be able to get to Silver II sometime. I main support and generally tend to lose the game if I play any other lane. It's not like I play that poorly when not playing support I actually tend to win my lane(if only by a little), the rest of my team just seems to do lack luster. This doesn't mean I'm the best support player either, I just tend to do my best there. I mainly play Leona, Nami, Janna, Lulu, and occasionally Alistar when he works. So it'd be awesome if any players(preferably support mains but all input is good) that could give me some tips on playing support in ranked. I've already heard the traditional don't feed and be positive, so I'd prefer not to hear more of that. Granted I'm not always the most positive player I try my best to do so, the game can just be extremely frustrating at times which can lead to raging especially if your team is blaming you. That's the other thing about being a support main, the extreme lack of appreciation. If your team isn't winning then why not blame the support, but if you're helping the team win you don't get any appreciation from most people. This post is mainly just to give me somewhere to rant but if you guys have any tips that could assist me in getting out of Silver III that'd be rad. Thanks for taking the time to read this and for your input guys(and gals)! I already posted this once in the forums but thought I'd post it here too so I could try out the new community forums.