Well it depends on what you trade and the method you use to trade with. If you are playing in penny stocks then life will be tough and it is more or less a gamble. Day trading normal stocks is less hit and miss but you can do ok at it. There are other things like currencies, commodities and indices just to name a few that you can trade but all are just a little different. I only intra day trade the indices and do ok at it and have been doing it for a number of years. It is not a gamble but an understanding of how the indices work. Of course every trade is not going to go your way but there are things you can do to address such situations.
Sometimes I use a mining analogy for day trading. Say I am looking for gold. I can dig a hole in my backyard in the hope that there might be some there but the probability might be low. I can go dig where other people have dug knowing that maybe someone had found some over there. I can also get a metal detector and just walk around in the hope that I might cross over something. I can also sit at the side of the creek with a pan hoping that some gold might come my way. But for some of us, we like to know what type of gold are we looking for. Is it orogenic gold, volcanic-hosted massive sulphide deposits, intrusion-related or alluvial gold?? Each one will require an understanding on how to retrieve the metal. You also need to be in the right place which requires an understanding of formation. You will need the right tools to extract the gold. Sometimes we are not going to find anything and sometimes we will find a rich vein. Trading is much the same. Sometimes you will find nothing yet other times you will find that vein. Just do not dig a hole in the backyard and then yell gold mining is just so random and a waste of time because I dug a hole and found nothing.