Patience for sure and maybe some empathy thrown in as well.  Us old fellas are usually trying to feel young again  

I agree with all the responses thus far, and a non judgemental attitude is a big help.  

In addition I have two thoughts.

First, touch.  If we are divorced, or have a wife who is non sexual, rarely do we feel the touch of a woman's hand or the warmth of a woman's kiss.  Many times I have spent the majority of a session being touched and kissed, ending in a BBBJ to completion.  Perfectly enjoyable.  

Second, you don't have to fake and orgasm.  At our age we know we are not studs anymore.  Back in the day I could cum twice and even three times.  Loved it too cause after the first pop I could take my time an focus on my partner's needs.  Those days are long gone.  We, at least I, do not need to have a lady fake an orgasm while we fuck.

A year ago I met a stripper (Bentley Marie....see review) who was very open about my time was all about me, and not to expect her to cum.  Most of the time she danced and teased as a stripper would, but I could do things not common in a club setting.  I digress.  Point is when she fucked me CG, I knew it was about my orgasm.  100% of her attention was getting me off.    

That being said, if you cum, great, put do not fake it.  

End of rant.  Great question.

Everybody knows it's an act, so the less phony and more natural you can act, the more "authentic" the experience.  Cuz most old farts have seen it all and are just going to roll their eyes when the acting goes over the top.