Re: red spot
If red spot is visible, than stop the kiln for refractory patch.
If shell temperature is increasing, the reduce the feed and use high liquid raw mix for coating formation.
And if your question is generic one, then there are lot of factors whereupon better coating formation depends for lasting refractory life.
Proper refractory selection, optimised raw mix and fuel for your plant conditions, burner pipe alignment are name to a few.