The primary consideration is her age. Scores at this age are notoriously unstable, and really shouldn't be considered more than a ballpark measure of current performance, rather than predictive of her long-term development or outcomes.
As to working with her to improve her scores? I would not do anything that you wouldn't naturally do as part of raising a happy, healthy, curious preschooler. Prepping for cognitive assessments is not recommended. Nor should she, actually, be tested quite so frequently. Typically, the recommended interval for valid results is 24 months between administrations of the same test. Although she will be eligible for the upper level of the WPPSI-IV next year, there will still be some overlap in subtests, which may result in an inaccurate picture of her. (Also, even a year from now, she will be very young, so all of the same caveats about unstable scores in small children still apply.)
The best things you can do with her to aid her development are the things you would do anyway as a loving parent--share a variety of interesting experiences with her, follow her lead in pursuing her own creative interests, listen attentively and converse with her, spend time with her, etc.
