I find that many churches are a little intimated by social media because they don't think they have much to post. Others who do participate in social media treat it as simply an online church bulletin or a venue to post scripture of the day.
It can be so much more, and if you take real advantage of your web site, you can have plenty to post that not only can appeal to members and potential visitors, but can drive traffic to your web site for more information and content.
It's all about recycling.
If your minister or other church leaders blog, even if they post to their own site, make sure thoses posts wind up in your web site as well (web sites powered by content management systems - CMSs - like Joomla or Wordpress can use add-on tools that can automatically import those posts). Use individual posts from your site as social media entries. Add a sound-bite-like quote as your comment.
If you post church information, news and events on your web site, organize the content so that each item can be linked to directly, and post the link to social media.
Are your sermons online? Promote the series or specific topic in social media, then post a link to each sermon in social media after it is loaded into your web site. Headline it with a quote from the sermon. Occasionally post a link to the series with something like "have you missed a few Sundays? Catch up on our current series here!".
Expand the content in your web site by answering questions your congregation's leaders get from visitors or those just curious about your church. Chances are others might be interested in the answers as well. Pick the best questions, and either blog your responses or post them directly into your web site. Now you have more to use in social media.
Do you have online registration for events? Put the event details on your site, with a link to the registration form, and promote the link to that event in social media.
Do you find articles by others on relevant church or Christiain topics? Post those directly to social media, again with a comment that draws people to click on the links.
Be sure to adapt your posts to each social media platform.
You may quickly find you almost have far more than you need to make your social media channels active, useful, appealing, and effective.