>>7713174 (OP)
don't look up "how to draw deer"
Look up "pictures of deer"
Then draw the outline of deer as simply as you can. With straight lines. just as a warmup.
Next, just take time to observe the anatomy. Literally just look at it for like 5 minutes and try to pay attention to the details.
Now try to draw the deer from memory. Don't use any reference material. Take your time
Then compare your memory drawing with the the deer. Pay attention what details you missed.
Next. Draw the deer using the reference. Paying attention to the details you missed in your last drawing.
Lastly, draw that same deer from memory. When you're done compare your first memory drawing with this one.
repeat with many deer pictures until you can satisfactorily draw deer. It may be useful to independently study different parts of the deer's anatomy with this method. Give time in-between each session to let things solidify.