How to (not) break into a new field

Over the years I have moved into new established research areas with mixed success.
Sometimes this has been a move from one sub-field of condensed matter theory to another. Other times it has been to try and cross disciplines, e.g. into theoretical chemistry.
I have also watched with interest as others have tried to break into communities I have been a part of.

Here is my list of suggestions as to things that may increase your chances of success.

1. Listen.
What do the well established experts in the field say? What are they working on? What do they think are the important questions? What are the key concepts and landmarks in the field?
Bear in mind the values and culture may be quite different from your own field.
Note: this is the economist Paul Krugman's first research tip.

2. Be humble.
Most fields have a long history and have been pioneered by some very smart and hard working people. That doesn't mean that the field isn't populated by some mediocre people or bad ideas or bad results or that you have nothing to contribute. But, don't presume that you actually understand the field or that your new "idea" or "contribution" is going to be well received. Treating people in the field with disdain and/or making bold unsubstantiated claims will increase resistance to your ideas. Don't be the scientist who cried "Breakthrough!"

3. Be patient.
Don't expect people to instantly understand what you are on about or how important your contribution is. It may take years or decades to be accepted.

4. Make personal connections.
Go to conferences. Talk to people. Slowly and carefully explain what you are doing. Learn from them.

Who is your real audience?
Are you just trying to impress your department chair, a funding agency, or your home discipline, by claiming that what you are doing is relevant to other research areas? Or are you actually trying to make a real contribution to a different community?

If you want to see a case of physicists not being well received in biology read Aaaargh! Physicists! Again! by PZ Myers about a new theory of cancer proposed by Paul Davies and Charles Lineweaver.
An article by Davies about his theory is the cover story of the latest issue of Physics World.

I welcome suggestions and anecdotes.