I really think taking a class is a waste of time and money. I suggest reading and putting the knowledge you gain to work. You will refine the craft of selling the more you do it. Read different authors, listen to guy on here, talk to other folks. Listen to people you interact with on a daily basis. Go with what works and what comes across as natural. Hone your craft.
I have been lucky, I have spent the last 13 years as a sales rep for both a HUGE "Fortune 50" company and now a smaller privately owned company. As a Manufacturer's Rep, I have spent lots of time traveling with Distributor reps. While doing this, I have learned both good and bad things to work on and things to avoid. I have seen great salespeople and horrible salespeople. I am like a scavenger, taking bits and pieces, making them my own, crafting them to suit my needs and my particular product. I have taken this experience and usedit with my own businesses.
There is nothing worse than someone that simply reguritates something they have read or learned, when it comes across as rehearsed it usually does not come across as sincere. People buy from people they like and trust. Practice, make it your own, "sound bites" from a book are ok if you make them your own.
"upselling, cross selling, hard selling, soft selling, persuasive selling, need based selling...these are all terms that descibe what we do, there are many more too, but at the end of the day, it is just you and your customer, you have to figure out what they need. Listen, Listen, Listen.....find out what they need, want and expect. Now it is time to sell.
We can talk about price, benefits, performance, equipment, references, etc., etc. but you have to understand what they want first.
In my opinion, there is no science to sales,it is organic, constantly changing based on what you hear from your customer an if you have a pre-determined script you are trying to remember and follow you will mis something.
The most important thing to remember.....ABC.