Just wait till you find that you've enough profit then convert it into your currency then buy again when price get low again rinse and repeat.
That will be a too long process. Rather than that start trading with a small amount. When you turn it into fiat there will be a fee, although now fees are there even on transactions. But that will be a more profitable thing to grow your BTC.
But buying and selling within exchange between bitcoins and fiat will not incur big fees. When we are showing some good volume, we will get discounts too. This process might be suitable for both active and passive (long term) trader.
When you are passively looking for right price levels, you might need to wait for longer haul still comparatively it may fetch you good profits.