wait and watch policy is right for purchase altcoin for the long term?
If the altcoin is top of the line but there are altcoins that are just like a pump and dump altcoin which is not worth it to wait for it in the long term.
if it is right then when we have to book our profit?
Easy, if you're in profit.
How much to watch if waiting?
Watch it just as you're watching the market if it is about to fall or rise.
When should we make a profit and get out of it?
any strategies on that.
No exact timeframe for that, it is the reason you need to watch the market closely and take your profits if it's necessary.