How to block spam commenting in my word-press blog?

How to block spam commenting in my word-press blog?

Reduce the number of links allowed per post.
Create a list of 'blacklisted' words.
Set up a comment moderation system.
Restrict comment privileges to registered users.
Use an anti-spam plugin, such as Akismet.
Move to a third-party comments plugin.

One simple thing you can do is to keep comments visible only after approval

Log in to your WordPress site as the administrator.
From the Dashboard, go to Settings. | Discussions (Figure A).
In the next screen, uncheck the option for Allow People To Post Comments On New Articles.
Scroll down and click Save Changes.