If you're into crypto-trading through an exchange like Poloniex and you're comfortable with storing value on such a platform then this an incredibly basic way to gradually increase your market share.
So essentially the idea is that you keep an eye on the price of ETH and BTC, I would recommend using BTC as your base currency as it is much larger and widespread which results in a relatively stable rate.
There's really not a lot too this; when the disparity between the value of these two arises, you trade into the cheapest, rinse and repeat, exploit the difference to gradually acquire greater volumes of coins.
So coin flipping; making money from the difference of two values, simple but effective.
(even if you make a mistake, you can keep going and trade back up)