Nobody can say what can be the "best" moment but you can do your own research on what the buy/sell points can be. In fact if someone knew from beforehand when to buy and sell to make maximum profit, then the speculative market would not exist.

I suggest if you are a newbie, dont think about weekly flipping. It is easy for you to comment that every week there is a flip but when you are putting your own hard earned money in it, you will not see it similarly. Dont go for the short-term flip, unless you have prior experience from stocks or such markets.

Try paper trading too, you might get a better idea. Dont assume things in the market, or it will mess up your head and that is something that will destroy your attempt to trade. Check charts, set up buy/sell points and paper trade on that - see how much you assumed and how much ended up being profit.