By default, the maximum execution time for PHP scripts is set to 30 seconds. If a script runs for longer than 30 seconds, PHP stops the script and reports an error. You can control the amount of time PHP allows scripts to run by changing the max_execution_timedirective in your php.ini file.

To change the maximum execution time, use a text editor to modify the max_execution_time directive in your php.ini file.
For example, to set the maximum execution time to 10 seconds, use the following setting:
max_execution_time = 10

memory_limit
upload_max_size
post_max_size
upload_max_filesize
max_execution_time
max_input_time

Editing php.ini File

The php.ini file is the default PHP configuration file. Most of the Shared Hosting Company does not allow access to this file. If you are certain that you have access to php.ini file on your server, you may proceed with the following steps.

1. Access it using your FTP program. (how to do use a FTP software with WordPress ?)
2. Backup a copy of this file before attempting to edit it.
3. Open it and find the following values, one at a time (They are located at different lines within the file)

4. memory_limit
   upload_max_size
   post_max_size
   upload_max_filesize
   max_execution_time
   max_input_time	
   

5. Preferably, edit them to the following values.

   memory_limit = 256M
   upload_max_size = 64M
   post_max_size = 64M
   upload_max_filesize = 64M
   max_execution_time = 300
   max_input_time = 1000