Hi Keith,

Usually native plants are best. You could have a combination of trees, shrubs and perennials that offer nesting sites for birds, food for birds, insects and butterfiles and shelter for small critters. Consider planting a few evergreen shrubs and/or trees for winter shelter.

I don't know where you live, so it would be difficult to say which plants would be best. I'm in the US in Maryland and would search at www.google.com and use terms such as:
wildlife + garden + Maryland
native tree + Maryland
butterfly garden + Maryland
native plants + Maryland

You might be able to just use the words:
butterfly garden

Let us know where you are and I will give you more sites if you are in the US.
Newt