With relationship based selling, the clue is in the title! To be successful with this type of selling you need to be developing and extending relationships. The activity is similar to networking except you are building a network within the client account. Seek to keep updated with what is going on and also expand your contacts. Getting an internal introduction from your existing contacts is a great way to do that. Ask your contact who you should be speaking to and then ask them to send an email introduction.
Eating with a client in the staff canteen is great for meeting new people. They will often sit with colleagues and then introduce you and that should lead to a friendly conversation. Learning to tell stories of other projects is a great way of sowing ideas in a soft selling kind of way.
Other ways of getting introduced include Christmas parties and staff social events like trips to the cinema. Get yourself invited and it makes getting to know people in the client organisation easier and less formal.
The relationship development activity is covered in the account planning sessions but it should be something that is natural and ongoing. Just like other types of networking, meeting people once is not enough. You need to nurture your relationships and often it is who they know that is just as important as who they are.
As mentioned before, soft selling is more appropriate. If they think you are only interested in what you can sell them then you might find it harder to get them to meet you unless they have a specific need. The aim is to get to a position where the client talks through their spending plans with you in advance so that you can shape their ideas and be in a better position to win the deals with little competition.