From b2evolution manual
This manual page is outdated. NEW PAGE: Tricky Stuff in b2evolution v5+.
 Completing installation
Once your installation is done and basically working, there are still a few tricky things you should definitely take care of:
- When you edit any of the config files, be careful not to add any extra blank lines at the start or end of the file. For some very tricky reasons, this will cause your cookies to fail where needed in the app, and you won't know why.
See also FAQ#"Cannot modify header information".
- Check your htaccess file
- If you get any file permission errors when running b2evolution, then you must take care of changing all necessary Directory and file permissions.
 Completing upgrade
If you are upgrading from an older version of b2evolution, be sure to follow on to the upgrading page and check if there are specific instructions for your specific upgrade path.
 Optimize your setup
If you just installed, this is not critical right now, but keep in mind we have a whole page about Performance optimization which will help you greatly enhance the performance of your blog by tuning your server configuration.
Make a note for later though, this can really help b2evolution run up to 10 times faster, depending on how your server is currently configured.