Shiny, smooth milk starts with knowing what you want to achieve, which is microfoam, not foam. A big, airy head that breaks from the milk below isn’t the goal, but rather a “wet paint” texture that flows as a cohesive mass. Use cold milk in a cold pitcher and fill it only up to the base of the spout. That will leave some room to froth and make it easier to control. Insert the steam wand just below the surface and instead of hearing a screaming “peeee” you should hear something more like a steady ripping “tkkkkk.” That tells you that the air is entering slowly, rather than too fast.
It’s more about positioning than power. Position the pitcher so the steam blows in a vortex, pulling the top layer into the milk. This will roll out the larger bubbles into smaller ones and will heat the milk evenly. If it’s just shuddering or splashing the milk, pull the pitcher down to the right angle until the milk starts to swirl in a circular motion and sit in the middle. Only stretch for the first few seconds and then hold the pitcher low enough so the steam doesn’t blow out. Now your main focus is on heat and gloss, not to aerate anymore. Too much air will make the froth chewy and it will not fold into the espresso.
While we do have a thermometer in our equipment, it’s easiest to gauge temperature with your hands when you’re first learning. Place your hand flat against the side of the pitcher, and remove from the steam when it gets too hot to leave your hand against for more than a second. Steaming too far past this point removes the sweetness and imparts a scorched or boiled taste that can’t be masked by pouring well. One of the biggest errors people make is holding out for a roll of steam or even boiling; chances are by then it’s already too hot. The milk should look silky and glossy; you shouldn’t have a layer of foam separating at the top.
Knock the pitcher against the counter and twirl it a bit just before you pour. This should shake out any remaining bubbles and make the milk consistent. If it looks flat or too foamy, the milk might have been over-run or old. New, freshly-steamed milk has an almost liquid-silky feel to it and will pour smoothly out of the spout without clumps. Pour from a bit higher up at the start to get the milk under the crema, and lower it down as the cup fills to allow the foam to flow to the surface. This is what will create the regular patterns without trying to.
Consistency is key. If you only try once or twice a day you will never develop a routine. Run a little steaming pitcher and dump into a cup, immediately do it again. Notice the pitch and volume when you stretch the milk and the look of the milk when it starts to form a whirlpool. After a couple of tries you will start to see a difference. Better sound and pour when you don’t stretch so long, sweeter milk when you stop the steam sooner, fewer bubbles when you run the steam more smoothly. Eventually your hands will figure out what to do and you will stop getting lucky with the milk; every latte will start to be a calm and methodical procedure.