I used to struggle with this a lot, and some days I still do. It's a hard mindset to get rid of!
For me, step one was to accept that there will always be someone better than me. There will always be someone effortlessly doing the things I still only aspire to. ALWAYS. No matter how much I learn, there will always be someone who has learned more, or differently, and discovered ways and means of doing things I haven't.
Step two is to realise that this is perfectly okay. You're always going to be learning, you're always going to have things left to learn. It is the same for everybody else.
The really difficult bit is the bit where you have to be able to look at the work and the achievement of others not as a source of envy, but a source of inspiration. The trick is realising that you're not supposed to strive to be better than them - you're supposed to be striving to be better than you.
Keep your old sketchbooks around. I stash mine in my bookshelf, and in a box under my bed. Any time I feel like I'm terrible and going nowhere, I dig them out and compare what I drew today to what I drew a year ago, or two years ago. In 99% of the cases, what I drew today is worlds better than what I drew a year ago, and I can feel proud that I've improved. I'm going places!
I know it can feel hopeless - I certainly have days when I just want to stop whatever I'm doing and go back to bed, convinced I'll never get anywhere or do anything worth doing! - but please tell yourself that the only way to fail permanently is to quit; as long as you keep going, you're going to be doing better for every time you draw!
Re: specifically looking at other people's reader-numbers - remember that you're only seeing the end-result. You didn't see the road they took to get there. Maybe they spent years building up a fanbase on another site, which transferred with them when they came to Tapastic! Maybe they got featured on the front-page! Maybe someone famous found their comic and told their followers on Twitter! The possibilities are endless, really, you're probably looking at the highlight-reel of someone else's life, and comparing it to your own blooper-reel.