Kasal has made a list of ways to NOT propose:

From their site:

One of the worst wedding proposals ever made can be seen in the movie “The Bachelor” where Chris O’ Donnell makes his proposal in the Starlight Lounge, a restaurant known among the locals as the place to pop THE QUESTION.

Why is it the worst? Jimmie (O’Donnell) proposes to Anne (Rene Zellweger) capping their three-year relationship with the very dry and very unromantic statement ” You win”. Needless to say, this kind of proposal did not merit the desired response. But who can blame Zellweger’s character. That’s is why this article sees fit to advise all those who would want to ask on the don’ts of popping the question.

Their list:

• Don’t put the engagement ring in anything edible
• Don’t overdo on the props
• Don’t invite everybody
• Don’t ask a complicated one

HubPages has some advice on how not to propose.  Here is a quick list of their ideas, for more information visit their how not to propose page.

• Never Propose While Drunk
• Never Propose Immediately After Sex
• Never Propose While Doing Something Else
• Never Propose Immediately After a Fight

ILoveIndia has some suggestions on how not to propose.  Here are their ideas:

• NEVER propose over the phone or the Internet. It is the worst you can do, as it is too impersonal. Loving is all about expressing your feelings, which do not come out over the phone or the Internet. It shows you are not very serious about the whole thing.
• Do not propose in front of a large crowd. You wouldn’t want to embarrass your beloved and then get embarrassed yourself if he/she says No.
• Do not be too humorous. It will seem that you are not serious about this proposal. Being too humorous while taking a serious decision spoils the mood and the ambience and blows up the whole thing.
• Do not forget your manners and etiquettes while proposing. Don’t propose while eating or while the person is at work. Give respect and you will get respect.
• Do not propose when you don’t mean it. Many people propose in the spur of the moment and then later regret their action. Do not give someone hopes and then smash it all at once.