If you are using Sublime, which is a very fast and lightweight text editor, to create smart contracts in Solidity, to get syntax highlighting, do the following:
⌘+⇧+P (command+shift+P) to bring up Sublime’s command palette, which is an interactive list whose purpose is to execute commands.
Start typing “install” and select “Install Package”.
Then wait a few seconds before another text box appears before typing “Ethereum” and select the first option.
To check that it has been installed, bring up the command palette and type “remove” and select remove package and Ethereum should appear indicating that it has been successfully installed.