The next step - content

Creating content
Right from the start, I am making the assumption that your site/page will be content driven - we need an idea of the type of information that we will be supplying on our niche website. Have a 'brainstorm' with yourself listing out all the topics that are covered under your niche heading and google for them to see what information is available. It is vital that the content eventually going into your site is unique otherwise you could be penalised by Google and the idea of monetising through Adsense will be a waste if time.
At this stage you could also consider whether there are other monetisation options open to you such as links to eBay or any of the other monetisation ideas that are documented elsewhere.
Do your research and thoroughly read through the information you have gathered until you feel confident that you have understood and can reproduce the content in your own style. Work out how you will arrange you content on the page or over several pages, you will then start to form ideas about navigation and how your site will flow. This is relatively easy for a small site, so think in terms of no more than about six pages or so initially.
At this stage I will probably be writing content into a document so that I can eventually copy and paste (my own work) into the site. The content should cover all the keywords that you want to be indexed for, you can work towards keyword density targets and the like, but I prefer my content to be naturally keyword laden - use common sense and try to use some keyword variation.
Keyword variation can be best illustrated by example. If your site is geared towards 'beer mats', you might want to occasionally refer to 'coasters' or some other related word - this has a two-fold effect, it prevents over-use of your keyword and it also helps to widen your SERP for an alternative search potentially bringing in more visitors.
Construction of your content into paragraphs, using headings and creating a logical flow of information is your aim here. This will give you the opportunity to insert Adsense banners between your paragraphs, but more on that next time....