1'st rule of trading; sell for more than you paid + fees every time. A doubling of your money can take 6 trades in one minute or 3 months, that depends on the market being wild enough while you look at the ticker.
Trading is not hard, just take luck out of your calculations meaning don't trade on what you think will happen, BUT ON WHAT HAPPEND! Very important that last point, then you wont ever loose money on a trade.
Is it even possible to DOUBLE your BTC in such short time? Why not just save a bulk of your BTC for the halving and invest a minor (but significant) amount in trading? You can dabble in the market without the risk of losing too much but when you will get to upsell then the profit will be definitely a step towards your goal.