What I have found is that the way to really impact the davening is to be a good example. I like to Daven loud and I try to daven with Kavanah and feeling and I find that when Im into it, it tends to rub off on the people sitting around me and they start davening louder and with more feeling. Davening is one of those things where you can really impact other people just by you doing your best to Daven with a lot of dveikus.
I would like to add that good Davening starts before Davening. the hachana and attitude we come to davening with is key to a successful Tefillah. If you go straight to Davening from conversation and shmoozing, well its not going to be easy to switch tracks and get into a focused davening state. I have seen people shmooze it up and then a second later roll up their sleeves and put on Tefillin. We need to think more about what we do. Bottom line.