If you spend money on marketing, make sure you track your success.
I love Google Adwords. I love them for two main reasons: You can target your ads to your audience and you can track how successful your marketing is. (I can write a whole other article about using Google Adwords to market your business, but Google does a great job of laying things out, so if you're new to this, go here and read up.)
My main point here is about measuring success of your marketing. Every dollar you spend is precious and you need to be able to decide whether it's worth it. If you spend $100 to get a person to your site and they buy $50 worth of your products, is this a good marketing campaign? NO. Know your metrics and track them.
Learn about Search Engine Optimization.
I am not an SEO expert, but I feel like I am slowly becoming one. SEO is critical to get people to find you through search engines.
To get started, check out this great article another member has shared: SEO -- What Is It and Why You Need It.
Also check out seomoz.org, which has some great free information about SEO as well as some tools to help you.
When you're ready for PR, check out PRleads.com.
To be clear, I get nothing for mentioning them here, but it is a service that we use at Work It, Mom!. For $99 a month you can get access to queries that reporters submit, looking for angles and sources for stories they are working on. You pick your topic areas (e.g. healthy living, women's interests, etc.) and you get leads emailed to you daily. You can then respond to reporters directly.
It's a process, so be organized.
Marketing isn't a one-shot deal, it's an ongoing process. If you're going to be serious about it, get organized. Create a spreadsheet with a tab for each of your marketing areas: Sites/blogs to contact/ Google Adwords campaign/ SEO work, and so on. Keep track of what you have done and what you have to do.
Do something every single day to market your website.
Or better, three things. That's my personal rule. I try to do three things every day to market Work It, Mom! and spread the word about it to as many people as possible. Some days this means writing a guest blog post for a partner site. Another day I might be tweaking our Google Adwords campaign or pitching a reporter.
Getting the word out about your site or product takes time, a lot of work and a ton of patience. Few things work as fast as you'd like and it's easy to get frustrated. But don't -- start with your three daily things instead!