Which knitting counter?
You can use knit counters to train Noticing things. But a tip: AVOID the digital counters and pick mechanical!
The problem: Digital counters shut off after a while, so you need to press the button twice: once to turn it on, then once to increment the number. After that, if you press the button twice, you'll actually increment twice if it hasn't shut off yet. The result is you always have to check if it's on or not. Terrible user experience.
Another disqualifier: at least with the most common types on Amazon, you will hit the button by accident throughout the day.
On the other hand, many mechanical counters are chunky. We need one that's both mechanical and compact. I've seen only one sort fulfilling these criteria, the "pendant style", the sort Agenty Duck linked: www.amazon.com/Clover-Knitting-Stitch-Counter-Kacha-Kacha/dp/B000WUXO4W
DIY finger counter: get a ring from a flea market (any ring), ensuring it fits your finger, and draw numbers on it 0–9 with permanent marker. So then you count by just spinning the ring a little.
If you want two-digit numbers, you can use two rings, or just track in your head how many times you rolled the 9 over to 0.
If it's hard to draw the numbers without smudging, try drawing Roman numerals.