Do your good deed for the day. You don’t have to be a popular blogger, an experienced blogger or spend a lot of time on giving another blogger a little help. This list comes from the SITS Girls forum.
Write a high quality guest post that will be useful to another blog’s readers
Leave helpful and insightful comments
Link to the blog and share your readers with them
Promote the blog in social media and start a social bookmarking campaign for them
Recommend to your readers to subscribe to their blog
Email the blogger with some suggested topics you’d love to see them cover
Introduce them to a potential advertiser
Share with them an affiliate program that has worked for you
Write an email telling the blogger how you found one of their posts helpful.
Perform a significant action for another blog. Don’t just leave a comment on 50 blogs; focus your energy on one other blog in your niche.