Trading have a lot of similarity with gambling with the difference almost insignificant. Your distinction id primarily base on the fact that you see trading as skill whereas gambling as entirely a thing of luck and I want to fault such line of thought because gambling too require skills and those who have the right skills are able to win gambling much more than those who approach it like it were just a thing of luck. On the basis of skill and emotions, trading and gambling are completely similar just that the risk make them a little different as the risk of trading is more controllable than that of gambling.
Trading and gambling are never the same. Many people think of trading as gambling, for example, if someone is ignorant and has no idea about trading. When he trades, it can be called gambling. Otherwise, if someone learns trading completely and trades, whether he loses or wins, it will not be included in gambling, trading is not gambling.
You never need skill to gamble. If you want to gamble on cricket, then if a team is a little bad, then if the team is a little good. Then you will be offered more money than the good team. In that case, you do not need to know much. No skill or experience is ever useful while gambling. But in trading, skill and experience are very important for a trader.