We strongly encourage you to center polynomials.

There is really no one omnibus optimization method that works well on all problems. JMP has options like Newton, QuasiNewton BFGS, QuasiNewton SR1, and Numeric Derivatives Only to expand the range of problems that are solvable by the Nonlinear Platform.

Some models are very sensitive to starting values of the parameters. Working on new starting values is often effective. Edit the starting values and click Reset to see the effect. The plot often helps. Use the sliders to visually modify the curve to fit better. The parameter profilers can help, but might be too slow for anything but small data sets.