Er, it seems obvious doesn’t it? But actually those listening need a bit of direction. It goes like this…
Firstly, make it clear if this is a personal toast (e.g. a Groom toasts his Bride in the middle of his speech) by simply looking at the person to which it is directed.
If you want all the guests to join in too (e.g. The Father of the Bride toasts the newlyweds at the end of his speech), you should look at the guests and direct them when proposing the toast:
Ladies and Gentlemen,
Please join me in drinking to the health and happiness of Rob and Laura
And then turn towards the person or people being toasted as you name them again: Rob and Laura