WordPress Posts Only Show A Few Lines Of Text
How can I allow more of the post to show?
Edit the template files in your theme. Start with index.php and replace each occurrence of the_excerpt() with the_content(). Then edit each post and insert the <!-- more --> tag where you want your post excerpt/teaser to finish.
You may then neede to make the same changes in category.php, archive.php and tag.php if your theme includes these template files.

ZenLite 2.1
[...] of your WordPress blog shows summaries of your posts and you don’t want to change that. So switching to use the WordPress more tag isn’t an option for [...]