Create a new project inside Unity and lets call it InitialUnityProject. You can add any initial assets here or add them later on.

Enable Meta files in Edit->Project Settings->Editor

Quit Unity (We do this to assure that all the files are saved).

(My addition) Create a new Git repository for your project. Setup git on your local workstation and pull the empty repository down to a folder

(My addition) Copy your new Unity3D project over to that local repository project folder.

(My addition) Create a .gitignore using my recipe or a modification as shown below.

(My addition) Startup Unity3D and open the project from the new local repository project folder.

For any operating system add the following to the .gitignore file

• Unity3D .gitignore file.

• Store this file at the root of your local repository.

• .DS_Store
• Library/AssetImportState
• Library/AssetServerCacheV3
• Library/FailedAssetImports.txt
• Library/ScriptAssemblies
• Library/ScriptMapper
• Library/assetDatabase3
• Library/cache
• Library/expandedItems
• Library/metadata
• Library/previews
• Library/guidmapper
• Temp
• *.pidb
• build

Note: remove the bullet points