Is there some area of your SAP experience that would really resonate with a particular business and a particular problem?
For example, if you're a SAP BW expert, you may be able to identify large retail clients who need to use analytics to identify which products and locations are doing best (or worst).
If you're looking to help existing SAP clients move to HANA, are you able to create a roadmap to help them overcome the very first hurdle in making the move?
Or you could aim at a particular position within a particular industry. For instance, you may be great at implementation of SAP HR for manufacturing businesses with over 300 staff.
Of course, you're not bound to go into a business centred around SAP, but if you draw on your existing experience to know who you work with best (and who you'd rather avoid), that can be an easier step than starting all over.
I wish you all the best as you head into a new business. It can be very helpful calling on the help of online communities (such as Clarity.fm), mentors or local meetup groups.
I think your biggest hurdle to success will be the issue of customer compliance.
As an employee of SAP, you got compliance from customers because of the weight of SAP: "our way or the highway". Correspondingly, those customers give up responsibility to SAP and say, "It's your problem now".
As an independent consultant, you will likely be surprised by the lack of this compliance in clients. Most will argue with you, think they know better when they don't have any understanding of the topic, and do differently than they agree--or do nothing at all. Even while they pay you.
If I was in your shoes, I would filter prospects for those who are willing to give that total compliance...and charge those clients a high value for the privilege. Otherwise, you're probably going to have a frustrating experience given your background.
That is a process suggestion. The question for you is: "What problem(s) do you want to solve for people?" Answer that and you'll know what business to be in.