If you could know the main move for the next day - why wouldn't you want to know that? Only if you can't accurately predict. If you could predict with some degree of accuracy, obviously that's an edge. The question is of course if one needs to predict or can simply succeed by following the market bar-by-bar. That's a different discussion.
The next day forecast is not your favorable strategy because you do not get decent leverage on stocks or stock index futures. So it would takes ages until you get a meaningful (account/position) size here. Unless you do swing or position trading which is totally different I would suggest you are looking for intraday strategies on stocks and indices. Usually Momentum plays are doing a lot of successful traders so that is term I would start to search for. Also Opening Range Breakout strategies can be to some extent useful because profitable (on Indices especially). Also you can search for Order Imbalance strategy at the market open for stocks. Decent leverage intraday you get for all futures and for stocks on some brokers and most prop firms.
The direction of the day determines its role in the context of higher timeframes. By understanding what is happening on those higher timeframes, it becomes much easier to comprehend the direction of the day's movement for tomorrow.