I agree it's best to always sell, of course, when there is a pump. But keep in mind that coins that go high tends to drop also. But it's just for a short period of time. So I would suggest that you sell on top and try to buy back coins from where first bought it. There is a big chance the coin will go back there. For losing coins, better cut of the investment as soon as you see the trend going down.
I normally use the market values to take care of every decision I want to make. Selling your coins at a time when you have the chance to make the maximum profit. This is only possible if you decide to sell off your coins when the price is high. Normally at a price which can give you 2X. Twice profits in Bitcoin could be instrumental in making you a rich man. A long term adds more than 2X profits.
I think that is what they call price action trading. You are basing your decision on price targets that you based on historical data. I heard thats a good strategy also.