Use the ten steps above, and you won’t go wrong. This list is by no means everything that you can do. They are, though, solid recommendations made after years of experience. The most important issue is to find a trustworthy person to talk to and demonstrate the alternatives available to you. Tangram has decades of experience waiting to advise you.
In the end, you might face making a very close call. Maybe you have to make the final judgment on whether or not you trust the person with whom you are dealing.
In particular, make sure that the person selling you the software is skilled in addressing your pains and can demonstrate how to solve them. The decision for a business system is not one you want to do again for quite some time, so make sure you feel comfortable with the salesperson and the vendor. If that is what it comes down to, go back to your research, so you can feel you made the best decision possible.