There are lots of things to consider. First, an attractive website is essential. What image do you want to create and what money do you have to try to achieve that image? Getting reasonable photos is a priority. Of course they are expensive but you can do quite a lot yourself with editing software.
There are lots of great hosts and templates out there now so you can set a website up cheaply and easily. Weebly is great!
I have chosen the image at the top of site to reflect, my passion for the fiddle, trad music and performing. I have combined this with a personal image so people know who I am!
What pages should you have? That will depend on what you want to do. My pages are designed with performance in mind (e.g. the News Page which gives details of upcoming gigs etc). I also have a hardanger page and links to my external website. A music teacher would have different pages.
I have loaded some sound files to give a flavour of the type of music I have been playing. You could do the same , or link to My Space, SoundCloud or similar.
Once you have your website, there are all sort of things that can make you site go up or down the rankings. You need to identify key words, you should write each page in a way that has quite a few of these (but not too many) or the search engines don't like it. Images should have Alt tags, Blogging frequently can help as can some links (but not all). Inward links to your site is a good thing.
You can also use things like Google ads. These can work really well, but it depends how niche your site is. I run a google ad for hardangers.com. You can set your search conditions and because hardanger violins is a very specific search works really well.
I wouldn't recommend a google ad for a search like "classical musician" though. Its note specific enough. But its great when it works.
Once you have merchandise to sell directly, a shopping cart would be great. But you can still sell through your site, through affiliate type arrangements (eg have an account with CafePress). I've tried this for another site I've run - its slow but with work it can provide a small additional income - especially once you've built a fan base.
Links to Twitter, Facebook are also useful and Weebly is about to introduce this into its new templates - great news! Can't wait.