I think it should be mentioned that the key to understanding the kart is to be smooth. I find most new karters tend to overdrive the kart and that complicates them gaining a feel for what the kart is doing. Most things like understeer and oversteer can be brought about from overdriving the entry or exit of a corner. But as one’s technique smoothes out over time, the kart’s handling subtlties will become more apparent.
If one has a Mychron and the ability to download data into Race Studio, I think that information can be useful in helping a driver smoothly carry speed through corners. I find slower laps almost aways have a less smooth RPM trace throughout the corners.
As TJ referenced above, steering input is a great indicator. Watch some YouTube videos of known fast drivers and note just how little they turn the wheel. Anytime you turn the wheel more than nessecary, you are effectively binding the kart with friction in some way. So less is more in this regard. Once you’ve pefected this, the kart will start talking to you more clearly because what you’re experiencing is more of the kart and less of your corrections.
Another thing I believe is important is to analyze each corner by three distinct zones: (1) braking/turn-in, (2) apex, and (3) exit. As you gain a feel for the kart, you should use terms like loose, neutral, push, hop, etc., applied to each of the three zones. Ask youself questions like: “Is it pushing going into this corner because I’m braking too late?” or “Is the kart getting loose as I go over those bumps on the exit?” or “Is the kart hopping at the apex preventing me from maintaining speed?” This will help guide you in set-up and what to try.
Lastly, the easiest changes to a kart are front track and tire pressure, so I’d start there to learn to read the kart as you can make these adjustments quickly and get back out.