Deciding to sell a performing stock

So I bought into ACLS and it has been a top performer in my portfolio. The target keeps get set higher by about 7% twice since meeting the original target. I thought of taking the win with 54% gain on the DCA, but it still is rising. Alternatively, I could sell a tax lot that is at 78% gain, but the stock is still rising. If I do sell then I would put it into something else that has been beaten up and that may not be rising. I know it is not smart to try and time the market and also smart not to marry a stock. I also thought about setting limits but the volatility of the market makes that tricky. Or I could hold for a couple more months and take as a long term gain. What are various strategies that others use?