Julia It sounds like I have a similar mindset to you, but I might be a few steps in front of you, so might be able to give you some advice that is helpful.
I'm web designer, I too have created a couple of sites that I thought could work well with my skills and earn me a passive income.
Although, I too got bored and sick of them... I no longer see them as a failure, infact what doesn't work for me, gets me closer to what I really want. It helps me sift through what I want and what I don't want.
I have learnt so much from these sites I created. So what value info did I come away from these sites?
Well doing these sites, brought me closer to my real passion.
I can put up a site together the way I want, because of my drive a determination.
I cannot work on sites that I am not passionate about.
I've learnt a lot about social networking and internet marketing.
Google ranking and SEO.
Don't start something up in an over-saturated market.
Doing these sites, made me realise what I am passionate about (or at least closer to what I think my passion is).
I now know I need to work on something that involves:
a community that helps each-other grow
a fun creative friendly environment
something where I can help other people to grow and other people want to contribute to help people grow
creative activities are done on the site for fun
something that looks aesthetically pleasing
I want a business where there is no real authority, the people I work with all want to create something great and love to work on it and help it grow.
My work colleagues will have fun and be goofy like me
I can't just sell a product, it has to go deeper than that.
I can't do affiliate marketing as it doesn't align with who I am and is far less people orientated. I would be just creating a product and then just getting money...that doesn't interest me.
I can't do something cheesy.
So if I was you I would look at what you don't like about these sites, I would assume it because you couldn't imagine yourself spending 24/7 on the content or product. The trick is to find out what you could work on 24/7. So now you obviously know a few things you already don't like working on, so break that down and say to yourself, why is that?
Julia start looking at what other entrepreneurs are doing and get inspired.
Look at Mixergy – Online Business Tips from Successful Entrepreneurs
and Internet Business Blog - Entrepreneurs-Journey.com by Yaro Starak
Start looking at what worked for entrepreneurs and what didn't.