Recognize the potential
It is very important to recognize the potential of the people who read your blog. Surely, if you need to recruit evangelists, they have to be people who follow you regularly on your blog or are followers. You have to look for people who regularly stay in touch. These fans will show great interest in your work and will email you regarding your write-ups.
Short list the followers who appreciate your work and constantly email you for help. These people definitely trust you with their issues and will be willing to work for you.
Post an ad on your blog
The next thing would be to place an ad, stating that you need a group of people for your blog or forum. Ask them to send their credentials through email so that you get a list of people who are willing to work for you.
Take your time on research
You must take good time to make the decision as selecting the best candidates will be good for you. Selecting the right people matters, even if it takes some additional time. Spend some time on analysing each candidate so that you have a clear idea of how each individual can help. Compare the list of candidates who have replied to your ad to the people you had screened out before to look for any common names.
Screen out the best candidates
If there are any common names from the two lists, email the candidates regarding the work you want them to do and ask for their opinion. Assign work to the hired evangelists and monitor their progress over the period of time.