First, determine the concept you want to trade, or the market phenomenon that you want to take advantage of. Choose a concept that you identify with, that makes sense to you and that fits your personality. You say "...
momentum...trying to take advantage of rallies and pullbacks". You should define that further, then you can choose the proper method, indicators, and/or tactics to trade that method.
For instance, personally I've defined my trading approach as trading 'short term momentum reversals'. I don't want to be in trades for hours, I don't want to sit through pullbacks. I want to trade momentum in the direction of the trend attempting to enter at the bottom of a
pullback, and I want to trade against the trend attempting to enter at the top of a pullback. I also want to be able to trade when the market is trending and when there is no trend, when the market is ranging.
Given these parameters, my research revealed to me, the most efficient way of trading this 'short term momentum reversals' concept is through
divergence. That is the market phenomenon that fulfills all these needs for me. This phenomenon made sense to me, and it fit my personality. This automatically said that I am not going to be a trend trader, also said that I am not going to be looking for home run trades, says that I am not going to use certain trade management like
pyramiding, etc. This also automatically cut down the field of indicators that I might use, and how I would use them. Also says, I am not going to be chasing after every concept the 3 guys next to me are trading.
Before you choose a trading method and tactics such as indicators,
price action, moon cycles, etc., fully define the trading concept that you want to trade.