When you've started up your espresso machine for the first time in the morning, it's important that you thoroughly warm it up -- from the inside out -- before you pull any shots. The easiest way to do this is to pull a 'blind shot' through the portafilter once your machine's boiler has reached proper brewing temperature.
What's a 'blind shot'? It sounds fancier than it is: Just insert your empty portafilter into the brew group, then initiate your shot. Let the hot water run through to heat up the internal pipes, the brew group head and the portafilter. Incidentally, this is also something you should do if you have machine with an E61 brew group that has been on and sitting unattended for more than 10 minutes.
Remember: Temperature regulation is probably one of the most important aspects of espresso brewing, so take the time to make sure brewing temperature is up to snuff. Otherwise, you'll end up with poorly extracted, cool, pale shots with little crema.
