My biggest issue investing is giving back too much of good gains. So I've been working on offensive sell rules and this is what I've come up with. Still a work in progress so this is just the beginning.

Use the attached chart for extensions above key moving averages.

Calculate market cap at time of breakout.
Small cap less than 2 Billion
Mid Cap 2-10 Billion
Large over 10 Billion

Once the average extension above the 200 day is reached. Look back at the uptrend since last breakout and determine which moving average shows the most obvious support. Sell on first close below that moving average.
Can use 10 21 or 50 day. If uncertain use the larger of the two

If the Top 10 extension is reached then stop changes to close below the 10 day.

If price continues up and gets above both 50 and 200 day Top Ten extensions then sell.

Some examples.
NVDA Large Cap break out March 2016
7/11 over 52% use 50 day as stop
11/11 over 68% use 10 day as stop
11/30 closes below 10 day. Sell