This is a meaty question with answers that don't fit neatly in this rectangular box, but will try!
First, make sure you are telling a story: Are you clear on who you are serving? Are you clear on the pain points to be solved? What is the change in the world that has caused those pains? How do your products uniquely address/solve/ease those pain points?
Secondly, within that story, make sure you don't lose the value props of the individual products. Not every buyer is going to be a multi-product sale from the start.
So think of it as an inverted triangle. Start with the broad story and get more and more specific. Change in the world, who you are solving for and the pain they are feeling, how you are uniquely solving for that at the multi-product level, how you uniquely solve those thigns on a single product level.