February/March is the ideal time for structural pruning and to reduce size and you can trim again lightly in summer for shaping and removal of any water shoots.

Apples need to be thinned in June to remove excess fruit. You want each apple to have 6-8 inches of leafy branch supporting it. Not thinning the tree properly often accounts for a lot of problems with small, misshapen fruit, broken branches due to weight and encourages disease and pest problems.

Most retail nurseries or garden centers in the area will offer free classes on fruit tree pruning around that February/March time frame that will be of benefit. I'd encourage you to seek one out and attend.