That's the Million dollar question isn't it. Ultimately your web presence itself will boost your ranking with google. The first priority of having a website would be content. Make sure each page has a good writeup of what its about, use your business name, location you serve, at least twice on your page. Inlude some photos ( make sure the pictures itself have your website on them as they are added to google images automatically).
If you have some tips for other event planners, make a video, put it on you tube ( put your website info on the video and in the tags) and post it to your website.
Join facebook, linkedin, and twitter and STAY ACTIVE! this will increase your web presence.
Join Message boards (like this :P) and post often using your website information in your signature.
Write a blog once a week, put your website information in your signature.
If you create your own website using the user friendly http://www.intuit.com, make sure you create a sitemap and submit it to google.
How do you do that? first [URL=http://www.xml-sitemaps.com/]Click Here[/URL] Then [URL=http://www.google.com/webmasters/tools]Click here[/URL] and submit your sitemap. Its easy and only take a minute.
Goto google places, add your business, and again add content to your "Place" Page, pictures, video, location of area you serve
Now goto yahoo and create a profile, rinse and repeat
This is not something you do once and forget. This is something you set aside time every day, and plug away. You could easily spend 8 hours a day doing this but you will drive yourself nuts. Just dedicate 20-30 minutes a day to add a couple posts here n there. Pretty soon you will find oppurtunities every where you go.