Sacred Haven of Debauchery

Don't make a casual, off-the-cuff proposal;
Don't propose when you're drunk – it shows disrespect to your girlfriend;
Don't chew, listen to music, or get distracted by other things during the proposal;
Never propose to your girlfriend over the phone;
Don't even think about proposing to your sweetheart after sex, in bed;
It's best not to turn the proposal into a show – many girls don't like excessive attention on themselves at such moments. So, if you still decide to do something spectacular, like proposing on live TV, think about it 100 times;
Hiding the ring in food is a cliché. And after such an evening, your girlfriend might end up in the dentist's chair;
If your girlfriend isn't a fan of any particular sport, don't propose at a stadium;
Don't propose in front of her whole family. For your partner, this will only lead to unnecessary stress;
If your girlfriend doesn't immediately say "Yes" but says "I'll think about it," don't make a tragedy out of it and don't express your grievances to her. For her, this is a very important decision in her life, and she is not obliged to immediately give you her answer;
Don't propose if you're not 100% sure about your girlfriend!

Talk to your beloved about the possibility of living together.
You should be sure that you both want this, and that you have no disagreements about your future (living with parents or separately, having children right away or in a couple of years, etc.).
Inform the girl's parents.

Note that you should inform them, not ask for their permission. After all, you will live with the girl, not her parents, so even if they don't particularly approve of your marriage, you don't have to listen to their opinion. By talking to the parents, you will not only show your good upbringing but also express your respect for them.

Choose the ring yourself.
Make a plan. If you can't come up with anything original, we advise you to contact special agencies that organize marriage proposals. Here is a link to one of the reliable agencies.