Hobbyist is someone that designs games hoping that people like them.
Pro is someone that designs games knowing tha people like them.
Hobbyist is someone that copy pastes code in an attempt to make a product.
Pro is someone that makes the game game that other people want to copy paste.
Hobbyist codes when he feels like it.
Pro codes full stop (whether he wants to or not)
Difference between a hobbyist and a pro is 1,000 billable hours.
A pro would say...
1) I don't care if you quit or not - what do you want to do?
2) Market research / Luck / but above all make better games. Flappy Bird is a 1 in a billion chance - not very good odds. Don't make junk games - make engaging, entertaining games that people want to lose themselves is for a long time.
Oh, spend $$$ for the best graphics you can. People buy good looking games, people continue to buy entertaining, challenging, funny, etc etc etc games