Trimming posts on v. 1.1.1

I’ve seen a post already that details how to trim posts on older versions. However, for this version (Version 1.1.1 | By etruel) the old thread no longer helps, as the codes mentioned there don’t exist anymore.

So… same question: If I only want to display x number of words, let’s say the 1st 300 + image, rather than the ENTIRE article, what should I do? I’d just assume comply with fair use policies if I can.

http://wordpress.org/extend/plugins/wpematico/