I find that a good strong espresso will give me a buzz within a few minutes. However each time I have an espresso the following buzz is reduced. If I don't have any coffee for a week or so and then have my espresso then I'll get that hit again.
Typically I have 1 cup in the morning and then maybe another just before I go back to work. There was a time when I was drinking a cup of coffee each hour and that was not good, when I stopped I had some really nasty headache / withdrawls.
After my son was born I started having strong coffee at work, 2 or 3 scoops of instant + a few spoons of sugar and only about 1/2 fill it with water. Again that would give me quite a nice buzz but I was adding scoops to keep getting that hit.
So if you want to use the coffee to perk you up before a meeting the best advice is to not overdo it during the week, drink lots of water to flush your system out and learn what kind of 'dose' you need because you don't want to go 'cold turkey' for a month before an interview, then just before going in drink 3 double espressos because you'll probably start sweating and hyperventilating. Just treat it as you would any other drug and don't get to the point where you need it to function.
As to how you take it... most coffees from your favourite coffee shop are espresso based, so a latte is an espresso + milk, an americano is an espresso + water... there's no real difference between one of those and a pure espresso, except that you're diluting the espresso if you add milk / water. Whatever you prefer is best though.