THE KITE DOESN'T FLY AT ALL
Perhaps there's simply not enough wind for flying a kite. 13-20mph of wind speed is the best weather for most standard kites. It is usually characterized by branches swaying and smoke moving horizontally. This is likely to be the case if you can't feel the kite pulling on the line. Just wait for better conditions and go out when there's more wind! Perhaps you can feel the kite pulling, and it moves left or right but just doesn't climb no matter what you do. That is the symptom of a towing point set too far back. Just shift it forward towards the nose of the kite a little and try again. Keep adjusting by a small amount until the kite willingly climbs into the air.
THE KITE FLIES SIDEWAYS THE WHOLE TIME
Holding the central axis of the kite, examine whether the weight of both sides are
balanced. Trying to increase some weight on the lighter side could possibly
work. Check if both sides have symmetrical structures. The asymmetry of area,
angle, hardness and softness of the framework can cause the imbalance of wind power
that results in side-flying.
THE KITE LOOPS AROUND AND DIVES INTO THE GROUND
Looping is usually caused by trying to fly when the wind is too strong for the kite. The first thing to try in windy weather is to shift the towing point forward a little. This reduces the pressure on the kite and might be enough to keep it in the air. Be aware that shifting the knot way too far forward in almost any kind of wind will make the kite unstable!
If you have shifted the knot several times without any success, it's time to add a tail or some more! Keep adding tail until the kite stays in the air, or you run out of tail material. If the kite is still misbehaving, pack up and wait for a less windy day!
THE KITE TAKES OFF AND CLIMBS, BUT DOESN'T GET VERY HIGH
In this case it sounds like there is enough wind, but the towing point has been left too far forward. Perhaps the last time it flew, it was adjusted for very windy weather! No problem, just shift the knot back towards the tail a bit at a time until you are happy with how the kite is flying. Make small adjustments, or you could end up with the kite not flying at all!
If shifting the knot doesn't help, then the wind is just not strong enough to carry the kite to its maximum height. The tiny amount of lift being generated is equal to the weight of the flying line plus the weight of the kite. It's a delicate tug-of-war between the kite and the line.