How is it possible for swing traders, trend followers, position traders, growth investors, value investors, and even some skilled day traders to all make money in the markets even with what is many times opposite strategies? There are three elements that cause profits in the stock market regardless of strategy.
Managing risk with stop losses. If a swing trader goes short at the top of the price range and is wrong and the rally continues then they will stop out for a loss when they know they are wrong while the trend follower rides the trend for big profits. At different times when support in a market is breached and the trend follower goes short and the swing trader goes long the market suddenly whip saws and gaps up then it is the trend follower who is stopped out for a loss and the swing trader profits. It is not the methods that make these traders the money it is the cutting their losses when they are wrong that enables them to have small losses when wrong and big winners when right.
Discipline. In trending market environments trend followers make very big profits and in range bound markets swing traders do very well. The key is for these traders to keep their past profits intact when the markets are not conducive to their style. They have to trade true to their method and not abandon it due to a losing streak, the longer the losing streak the better the odds are that the big winning streak is just around the corner. Markets go through seasons and traders have to keep taking their signals until their streak begins. It does no good to be a trend follower and suffer through a trend-less quarter losing money then when you give up to day trade a huge trend develops in the next quarter and you miss the gaps in one direction due to day trading only. Stick with one plan and execute it over the long term. If you do choose to use multiple strategies it is best to separate those accounts in my opinion, so you can keep focus on each portfolios strategy.
Faith. No system will work if you do not believe through your own studies that it is a valid, long term winner. You also have to have faith in yourself that you will execute your method correctly and take your entries and exits and manage your risk through stops and position sizing.
Almost all traders that manage risk, are disciplined, and have faith in themselves and their proven method will make money. However it does not matter how good the trading method is if the trader does not manage risk, trade it with discipline, and have faith in it, they will not succeed.