We came to the pleasures of coffee relatively late in our lives, having mostly been dedicated tea drinkers prior. Now, after discovering truly great espresso in Italy, we enjoy espresso and cappuccino some mornings. While we are still on the journey of great espresso, we have learned a few things, in order of importance (for us).
Buy freshly roasted beans from a good roaster; we love our local 49th Parallel Roasters. The key is to buy fresh and grind yourself as required, storing the beans airtight and cool. Do not suffer through old beans, or worse yet pre-ground coffee out of a tin.
Next, buy an excellent ceramic burr grinder. We found that this makes even more of a difference than the espresso machine, if possible. The key is a grinder that will produce a fine and consistent result for superlative espresso, without heating the beans. Experiment with the grind setting etc for your portafilter (group handle), machine, and desired style and flavour of liquid black gold, but start with a very fine setting first.
Lastly, acquire an espresso machine that has your desired features and attributes. There are many published thoughts on the latest and greatest—we can offer no specific advice, other than undoubtedly you will need to practise, practise, practise on whatever machine you get. Use a naked portafilter if possible, and VST filters are excellent.
As you learn, perhaps adding a scale, timer, and dosing tools to your arsenal, your espresso will get better and better. Dedicated espresso, cappuccino, and latté cups are fun too. Oh, and if your coffee machine comes with a light plastic tamper, invest in a proper, heavy tamper from Reg Barber.