There are a number of ways you can do this and I use a few different social media management programs that allow you to manage multiple accounts, post content on a regular basis and setup a schedule where you can post content from different sources to your different accounts. Sometimes you can post every hour of every day, or just once a week. The key is having the content and then setting up a schedule to have the content posted on certain times of certain days.
MONITOR YOUR SOCIAL ENGAGEMENTS
You also want to monitor your inbox and engagements of your social media content. If people have questions and post to your wall, the sooner you get back to them, the better. If people make comments, respond if you can and the more engagement that you can create, the better.
CREATE UNIQUE CONTENT, IMAGES AND VIDEO
Make sure you create a steady flow of new content, custom images and videos around the content. You can also currate content and find other blogs that have interesting or related stories and post those on your social sites. You can create a content queue for your facebook account and just have content post to your facebook page, then have a queue for your Twitter account and all other accounts.