When to sell JetAirways ?

hi, i do mock trading right now.
i bought Jet Airways (NSE) a couple of days ago at different prices
100 shares at 543/sh
200 shares at 549/sh
100 shares at 548/sh
i bought them because of the speculation that Jet Air will be offloading shares to Etihad Airways. When i bought them the price had already hiked at 8%.
And portfolio managers at Moneycontrol.com said the price could shoot up to 700/sh if the deal strikes so hold it.( some even say to 800/sh)

Today in the first hour of trading itself , the price shot to 562. i sold 100 shares. 300 shares i kept and hope it will soar even high but instead it was stable at that price for long and then fell and the closing price was 532 as compared to 545 at which i bought.
Did i do a mistake by not selling them off?

Im a newbie, this is second day of my trading ( i do mock, right now).
I want to learn when is it appropriate to sell off shares.how to analyse it.

Dear sam,

even I have brought some shares based on a call from bsenseguru dot com which suggests a buy on the stock with a target of Rs 1150, as i have always had the best predictions from them in the past and their call having worked all the time, i suggest you hold this for a 2 months horizon. you may make windfall gains.