Hi,
First of all try to isolate your web-application in local network for testing. That is the best practice.
Another best practice is to liberally use the "Wait" method on page navigation. You might also want to increase your object recognition timeout under Tools -> Current Project Properties -> Playback -> Auto-Wait timeout. Increasing this will give more wait time to allow for slower rendering.
Something we've done is built additional methods and routines that we use for certain tasks within our application testing. We have a panel that appears when there is calculations going on within the page. Whenever that panel appears, we make sure we have in our test case a call to a method to wait for that panel to close before continuing the tests.
However, as baxatob said, if possible, it's better to move your web application testing into a local network location to eliminate any connectivity issues. This ensures that you're tests are reporting only problems with the application and not problems with your connection to the internet.
