Open index.php of the wordpress theme and look for and replace with This will line up posts with summary. It is an elegant way of showing blog under categories and archives. For more information refer to this
which file you have edited? It should be the index.php under /wordpress/wp-content/themes/yourtheme/index.php and it should look like this If that doesnt work, try this..
Here is what you have to do.. To show summary of posts in categories, open page.php and look for this code replace with If you need your archives to be displayed in the same summary of posts, open archive.php and do the same changes. All the Best!
modifying page.php file is for wp pages, and when i change archive files then it works for categories. THANKYOU
There is a plugin which makes this process simple at http://www.thunderguy.com/semicolon/wordpress/evermore-wordpress-plugin/ . You can customize the length and appearance of the blog post previews.