Knowing when to take profit when trading news release

By setting bollinger bands, would it good for example, once the price stretches out of the bands, I start taking profits? As the market is self correcting.

True?

I'm also looking at using BB as a way to test buys/sells. I'm trying a 30M chart, shorting when the candles break the top, and/or buy to cover/go long when they break the bottom. I've looked at the history of one chart, and though I may have missed a few trades, overall it looks like a decent theory. I will giver today/tomorrow, and see what happens!

yeah, 99% of decent theories don't work in the real world.

How about trailing stop? Simple as that.

Then work out few ideas on demo check which one lets you keep the most profit and go with it. But I'm afraid that you will find out that simple trailing stop will be best idea. However as I mention try different ideas on demo and compare.