If you haven't already, make a drawing of your
land or print it from Google earth. Then use tracing paper to create a drawing, with features such as slopes, rises and low points, compass directions and sun light pattern.
If you can make more than one copy of this Base drawing so you have extras to use.
Next list out animals you want to have, as well as a plant/ tree/ shrubs.
If you can, determine how much
water you can collect from roofs. This can help with determining water needs.
Determining the flow of rain runoff is also a good thing to already know, that can help the consultant make suggestions on ways to keep that water where you need it. Again this is one of the things that drawing will be indispensable for.
If you already have ideas of what you want for the end goals, write them down in the order of importance to you.
The more things you can list, the better the results of the consultation should be. Drawings, and lists are the tools needed for giving and getting the best advice possible.