This video describes a number of the most important configuration files within MAMP that are commonly edited in order to run a web application like Drupal locally. There's a brief tour of the http.conf file, and then walks through the process of upping the max_allowed_packet limit from 1M to 2M within the my.cnf, which was a renamed copy of the my-large.cnf file. It's also a good idea to turn off binary logging on your local development by commenting out log-bin and binlog_format lines within this my.cnf file. Addi then shows you how to raise the PHP memory unit from 32M to 256 by opening the php.ini file and changing the memory_limit value. Finally, she shows you how to use MAMP's version of PHP and MySQL from the commandline by editing your .bash_profile and adding a number of paths to your default PATH. Note: The configuration files may have moved between versions of MAMP. You should check for where the MySQL cnf files are for your specific version of MAMP. A quick Google search can probably get you set in the right direction.
To learn how to install MAMP, see the Installing MAMP Server tutorial.