First, you’ve got to be friendly. You know firsthand that being an assistant can be stressful, and everyone you come in contact with is in the same boat, so a little kindness can go a long way. For starters, you should always close your your emails with a thank you. Think about the people you've enjoyed communicating with in the past -- aren't these the ones that always say thank you? Also, an exclamation point can go a long way -- in some cases, it can actually be considered rude to sign off with anything else. Putting an exclamation point after a thank you is an easy place to sneak one in, or you could say “Perfect!” or “Great!” after you’ve settled on a meeting time. You’ll come across as more personable and approachable this way, which will translate into more invitations to drinks than your less-friendly counterparts.
Secondly, you need to be fast. Don’t you hate having outstanding items on your to do list? So does everyone else. Respond to emails as quickly as possible -- others will appreciate it more than you know, and you'll minimize the risk of forgetting to set a meeting or waiting too long, which could result in some reprimanding from your boss. Even better -- assistants that reply to emails immediately appear to be smart, efficient, and organized, so when they’re looking for job referrals down the line, their contacts will have positive things to say about them when submitting their resumes. Just be careful that you don’t substitute speed for accuracy -- scheduling mistakes are very obvious and easily tracked via paper trail, and frequent errors can be extremely detrimental to your reputation (and your job stability).
Finally, you should do your best to be accommodating. You have more power over your boss’s schedule than you realize. You don’t want your boss to be the one that’s “impossible to get a meeting with” -- it reflects poorly on him and on you. Even if your boss has an extremely tight schedule, make an effort to show that you’re trying to fit people in, be responsive, and do your best to avoid last-minute cancellations. If you’re a good assistant, you should be able to anticipate when cancellations are likely and give the other person a heads up.
If you can remember these three simple things, you’ll be doing yourself a lot of favors. Other assistants love to gossip about the person who sucks at scheduling meetings, and that’s a big problem -- not only does that person appear inefficient and dumb to his peers, the same negative information will travel up the chain to executives. But an assistant that's always on the ball is well-respected across the industry. So before you send out avails, take a moment and think about how you’re coming across -- if you play it right, this basic task of scheduling meetings can really get your career off to a stellar start.