Most charities now have the ability to set up personal fundraising pages for each of their volunteer fundraisers.
Assuming your charity is able to provide you with a personal page, the first thing you should do to raise money is to personalize your page. Update the page with your story- why is this cause important to you? Why did you decide to raise money for this charity? What is the money used for and why is that important to you?
Next, add a picture of yourself. It is important for people to connect with who you are as a person and pictures always help. Even think about adding a video that helps explain why this cause is important to you. You may want to include family or friends that have an important tie to your cause. Make the video as personal as you are comfortable with.
One last thing to consider is creating a blog about your efforts to raise money. A blog can really help get the word out to people all over the world, especially if you are planning to continue raising money for several years to come. Check out wordpress or blogger as free blogging platforms.
Don't worry. Your blog will not be all about asking people to donate, in fact, if that is all you blog about don't expect many donations. Instead, make the blog about your fundraising journey. Use it more as an update or newsletter to your supporters. Make sure not to ask for donations more than 15-20% of the time, at most.
I will write more about how to leverage your blog in the future, but for now just get it started and make sure to cross link your blog and your personal fundraising page. Believe me, you never know how someone will find your fundraising page and make an unexpected donation.