Hold a large picture of a deer eye up right next to your deer eye and make adjustments. Do the same for the nose, mouth, etc. Do it again the next day, and so forth until it's dry. Also, click on pictures on here of people wanting critiques and look at their deer. Try to pick apart anything specifically that seems wrong to you and figure out how you would fix it. Then read the other critiques and see what you missed. The more you do this, the less you'll miss.