A toast honors a main guest at an event or acknowledges some circumstance, like the end of a war. That's it. That's what it does. Nothing more.
There are traditional toasts based on years of retelling, and there are customized ones, which is where I come in.
The tone may be formal, funny, casual, or solemn. It might draw from classic statesmen and poets, or even the Bible. There are rules, but, the same time, no rules. That is, there are general guidelines as to what a toast should accomplish and how it should get it done, but, truly, you can do what you like.
For example, if several friends are gathered to remember another friend who has passed, it is natural to be serious and somber. But what if that friend was the life of the party? Surely he wouldn't want to bring his friends down. Far from it. In that case, you can break the rules and help everyone laugh.
A toast can end a speech, be one among many toasts, or stand on its own.
A toast might start with the toaster standing. The visual might be enough for the audience to recognize that they should give him attention. Or, a tapping of the glass can get the job started.
Everyone may or may not stand, but everyone should drink.
Typically, alcohol is the category of drink used, but non-drinkers can be completely comfortable lifting a glass of water instead.
The person toasting should hold their glass at shoulder height, to their right or left so as to not block their face.