What is the best way to handle errors in plugins and templates? What's the best way to prevent exceptions in my plugin from blowing up my entire page? try/catch and return null, and then check for null in the template?

For example: my plugin fetches data from a remote REST API. If that request fails for any reason I get an error page. I understand why, but I'm looking for the best way to handle it. I'd appreciate any input, even if it seems glaringly obvious to you.
Yep, Craft makes pretty liberal use of try/catch blocks. Wrap your HTTP request in that, and return whatever makes sense in the context – null, false, or maybe an empty array.

Probably also worth logging the error, so the developer can investigate why it’s not working, using Craft::log().

Remember when catching exceptions, that there’s a good chance the exception class won’t be in Craft’s namespace. So you’ll probably need to prepend the exception class(es) with \.

So to put it all together:

try
{
    // Make the HTTP request
    // ...
}
catch (\Exception $e)
{
    Craft::log('The request to domain.com failed: '.$e-&gt;getMessage(),
               LogLevel::Warning, false, 'mypluginhandle');

    return false;
}