AppCleaner as advised above, only for any Apps that you install that you decide you don't want, and that don't come with their own uninstallers!
OnyX to perform basic clean up/maintenance every 2-3months. Use the automation tab, and the default selections in the action.
Other than that, better if you just enjoy your Mac on not get into the Windows paranoia, and also get to know your Mac well before you start messing with something that is good by default.
I would advise going to
Apple - Find Out How - Mac Basics and going through all the tutorials at your own pace, and getting a little familiar with the way a Mac works.
DON'T install any Anti Virus Software, unless you are installing a Windows OS, and then only install it on your Windows Partition or VM.
If you need anything in particular, please post a thread here in what you are needing, so that recommendations can be given to you, rather than having everyone come into this thread with their preferences telling you what you need!
Welcome to Macs, and Mac Forums, and please, if ever in doubt, ask first, and don't let anyone (friends or computer techs) install anything on your Mac!