Every time you make a sales presentation, always be thinking about what the add on sales may be. If you wait to think about this until after you close as is commonly done , you tend to be too rushed and forget the whole add on process.
Thinking about these sales during the presentation will enable you to be ready when the time comes to ask for them. In addition, many times, the suggestive sell of the add ons can help close the sale of the first item. By using this technique, you increase the potential for the total sale, and decrease the amount of time you would use if you were to sell each item independently.