Making money online requires a single idea at first, one cracking idea that is based on your main interests or hobby, this is the best way of motivating yourself to actually make money with something that you hold an interest in is much more valuable to you. If you like to dress up in womens clothes then why not create an idea around that, research a niche for transvestites, find where they hang out, what problems they face, make up tips for men dressing as women, that is only an example by the way, I'm not saying do this if you are against this type of thing, but sub niches are based on real life situations of what certain people go through or are gravitated towards, So why not try to cash in on it and have some fun in the areas that make you smile and be happy.
A good example is of mine, I really have a strong interest in drawing fantasy art and monsters, this type of thing could be made into a money making small venture and it is something I have in the pipeline, drawing relaxes me, so if it has that effect for me others will to, try and create angles and benefits for your intended area or expertise, ask yourself what would help others who like what you do?
Finding demand for the information you intend to create can be done by surveying your visitors or those that you interact with in your niche area, forums are the best place to find out problem statements of this nature, this way you are finding out solid information that will shape your business in an affiliate capacity or as an online business. Solutions and the needs of the masses can be fulfilled in almost any business area, so seek out anyone who needs a solution and get to know them better through some good old fashioned communication.
While technical aspects need to be found out about in all honesty as you can't get by online by just an ignorance of web technology, optimized content that is search engine friendly and seo(Search Engine Optimization) techniques really help with your online business for your site to get found and searched thoroughly and also the optimization of each page must be taken into account, because not everyone is going to find you through your home page, so spend sometime on your other pages with good keyword variations that compliment your main keywords.
Back to your money making idea, the one thing that you must provide is value above all else, if you don't have that, you don't have much. So by making your idea focused around a passionate topic or of subject matter you can really get your teeth into, you can bring something enthusiastic to the table and build something solid from there. By giving something for your visitors to do on your website, whether that is subscribing or signing up to your list, buying a product, clicking a link, calls to action are important on any site, because this makes your site interactive and hopefully more popular.
Making money online has several advantages that off line businesses don't get, for one you can start up with low capital and start straight away without having to wait for anything to materialize you just get on with it online, write content now and publish it later, upload pictures, get a web host account with domain name which are fairly inexpensive, like any business a marketing plan is involved but the readiness to start now is far better than a brick and mortar business were you have to wait for loans to be paid to you and the funds to become available and premises to secure.
A single online business idea can be worked out online actually as you are building it, from scratch, from the beginning, cause and effect, writing in your notepad then transferring your content to your site and designing it or getting someone else to, the best thing about starting an internet business is it's quite a quick process, one that takes minimal planning but also long term commitment, a good idea builds over time and the entrepreneur within you is more willing to take risks and experiment with web technology such as web 2.0 and affiliate marketing.
So once you have an idea, don't let it stew, let it out, show it to the world, see what people think, build on it and just try instead of not doing anything remotely unique and interesting, you yourself have a unique take on the world and something to give, so show it to the world!