If you are the patient type and have some spare change I have a slow but possibly profitable strategy for you!
It goes like this:
Buy a fixed amount in fiat of BTC every x period of time for a longer period of time while BTC is recovering from the last trip to the moon, and make a note of the purchase in your portfolio. You can preferably use an online portfolio or an app that automatically displays the value change of each buy. Sell with small profit when you have the chance, or wait until next time BTC increases fairly in value again and start selling.
Examples:
Buy 10 USD worth of BTC every week. You will spend around 520 USD per year.
Buy 10 USD worth of BTC every day. You will spend around 3650 USD per year.
Buy 100 USD worth of BTC every week. You will spend around 5200 USD per year.
Over time you will have a lot of small buys on a lot of different values. Follow the value on each buy and wait.
You can then either wait until all your buys are in profit in a distant future and start selling 10 USD of BTC every day while the price increases.
Or you can select individual buys and sell when the specific buy is in profit.
In a perfect scenario you would accumulate BTC over time and in a few years find yourself at a point in value and time where you can start selling with a profit on every sell.
Logically your small buys will loose value if the value of BTC is declining, but if you buy every day or week chances are you can sell again with a profit pretty fast when the BTC value goes up and down due to the volatility. This way you can make small profits many times.
If you have a lot of patience and BTC does another massive increase in the next 10 years, something most people think will happen, you might be able to sell with a massive profit while only investing a small amount every day/week/month.
Good "luck" :)
Ps.
You can buy some other stable cryptos and mix it in for fun, ETH, LTC and the rest of the usual suspects, and maybe throw in some high risk coins now and then just in case.