I finally discovered that the secret to getting a decent crema out of my De’Longhi coffee machine was to load in about 30% more coffee that I would normally do. I spent way too long thinking it was all about how hard I tamped down the coffee and trying either a lot of pressure or very little - that seemed to affect how fast the coffee came out of the machine but very little else. The De’Longhi seems to have a fairly feeble pump and if you tamp the coffee down too much the coffee drips out at an infuriatingly slow rate (once I got no coffee and just a lot of steam escaping from the gasket).
Update 6/11/2021: Maybe you’re wondering what types of coffee drink exist. In this case you might find this article The Ultimate Guide to Coffee in Italy useful since it covers what drinks you can get in Italy and where to get them.