1. Take selfies
Meghan appears to have already mastered this rule. While she was attending her first official event with Prince Harry in early December, the future royal purportedly told a couple who asked for a selfie that "We're not allowed to do selfies".
She probably won't be able to use all the fun Instagram and Snapchat filters, or post selfies of herself on social media, either. Say goodbye that puppy filter, Meghan!
2. Go out in public alone
Like every member of the royal family, Meghan will have security accompany her wherever she goes - for obvious reasons.
3. Sign autographs
Aside from official signings at royal engagements, royals are prohibited from signing autographs for the public. The reason is that someone could forge the signature and use it against the family.
4. Use social media
Meghan will probably be joining Harry, Kate and Will under the official Kensington Royal social media accounts. The trio have been updating the public on the charities they have been supporting, and having one account provides an insightful, but controlled, line of communication between the royal family and their citizens.
5. Show public displays of affection
According to royal etiquette expert, Myka Meier, though there's no official protocol against PDA, "Meghan and Prince Harry holding hands at a royal engagement is a refreshingly modern approach to their new role both as a couple and as representative of the royal family.” As such, we're unlikely to see much in the way of smooching going forward.
6. Vote
Although Meghan will be granted British citizenship after her marriage to Prince Harry, it's unlikely that she will participate in future UK elections. As the official parliament website states: "Although not prohibited by law, it is considered unconstitutional for the Monarch to vote in an election." While this applies to Queen Elizabeth II, a spokesperson from Buckingham Palace told Newsweek in June 2017 that extended members of the royal family choose not to vote "by convention".
7. Wear dark or colourful nail varnish
According to royal protocol, royals are only allowed to wear "natural" coloured nail polish at official events.
8. Cross her legs while sitting
It's frowned upon when a female member of the royal family crosses her legs. Certainly, Kate Middleton can often be found sitting in "the Duchess slant", which sees her legs slanted to one side.
9. Go to sleep before the Queen
This, thankfully, only applies when Meghan is staying in the same place as Her Royal Highness.
10. Open presents on Christmas day