This started as personal notes on how I to approach tasting my coffee each morning — with a few tweaks, this became my guide for tasting anything.
Take a deep breath in through your nose, out through your mouth
Take note of your feet against the ground
Take note of your hands
What does it look like?
What does the smell remind you of?
What does the taste remind you of?
Sweet - Sour - Salty - Bitter - Umami
Flavor - see "Basic Tastes"
Texture - how does it feel?
Finish - how does it end?
Memory - what does this bring up?
Write down your thoughts to others or your future self. This forces you to articulate half-formed thoughts which will be hard at first. But you'll only get better by doing it.