For a start, that is EXTREMLY good advice from Jobabob. Your first map will pretty much be crap. Secondly EXTREMLY gr8 words from Andy. Now I'm not the greatest mapper in the world thats for sure. But so long as I think pratically then thats ok. I think the best thing to do is NOT to make a big Hooha about ur map and let people find it themselves. When you start saying things like "Best map ever!" or "This is a great map!" then other peoples expectations will rise and they will most definately expect more out of your map, something it perhaps cannot deliver.
My first released map (not my first ever map) received an average of 3 stars, which is pretty pathetic. Back to the drawing board. Keep designing, keep trying other maps, get ideas, map it out and get a close friend to take a look! As Andy said above!
The best practice would be to expect a neutral review. Don't expect poeple to acclaim your map and don't expect people tp critisice your map. Then you can truly come back and say "How can I improve?" and then do it!
I finish by saying everyone gets better over time, just depends on how much time it takes. Just make sure you take the time!