1. Delete unwanted applications from /Applications (to go to this folder type "/Applications" in Finder -> Go -> Go To Folder
2. You may deleted unused application earlier or now, So check the folder ~/Library/Application Support for any related data exist for the deleted applications. You can remove delete that too. (If you are not sure when deleting, then take a back up to any external disk)
3. Go to ~/Library/Caches and delete all files inside the each folders. Don't delete the folders inside the Caches. This case also, you can take backup.
If you are a iOS developer,
4. Delete unwanted simulators from the path. ~/Library/Developer/Xcode/iOS DeviceSupport/
5. Delete Archived files from ~/Library/Developer/Xcode/Archives . This will delete all archived apps which we seeing from Xcode -> Window -> Organizer
6. Go to Xcode -> Preferences - > Locations tab . Delete all 'Derived data' (~/Library/Developer/Xcode/Archives) and 'Archives' (~/Library/Developer/Xcode/DerivedData). Tap the -> arrow key to navigate to the folders.
