Bring people into conversations: engage with Influencers with the Instant Influencer-Tagging tool
Easiest way: click in a word in your Tweet in progress and then, the Influencers button for a gallery of influencers that are click-to-add.
Also, you can click a hashtag in your post (in Twitter, Facebook, Google+, Tweetdeck.com (site, not software), Hootsuite, Buffer, Sendible) and then pull down in the search widget to Influencers. Scroll through them, see their follower counts, open their Twitter profiles, and when you’ve made a selection, click to add them to your tweet. If they watch their mentions, as anyone who truly engages in Twitter must, they will see your Tweet.
Also, in your Enhance Settings, you can make it a default to add author attribution (when possible; this depends on the metadata of pages you're sharing and cannot be done for all).
Tip: never mention more than one Twitter account in a Tweet so as to not appear spammy.