Say it out loud
If it needs spelling over the phone, it will need spelling forever. Avoid hyphens, doubled letters at word boundaries and anything with an ambiguous homophone.
The extension matters less than people think
A .com.ng signals a Nigerian business clearly and is easier to obtain than a matching .com. Consistency across your website, email and invoices matters more than the extension itself.
Register defensively, lightly
Take the obvious variants you would be annoyed to lose, and no more. Portfolios of defensive domains renew forever and are rarely worth the annual cost.
