What's the best way to invest? Wall St won't tell you the secret, but here it is: don't. Find a good money market fund as your base, and clip coupons by building a high quality relatively short duration bond ladder. It's essentially risk free, and it has beaten the market for over a decade now. Sleep well, save well, focus on your career, and enjoy your life -- and though you may not believe me, I guarantee you'll beat 95% of all investors in the long run, and you won't have to pay any "advisors" a nickel.
The prices in the market is always depending on the demand and supply so you can wait for the prices to decrease even more before selling your coins, dumping of prices in the market means you need to invest even more in order to earn a huge amount of profit.
the best time is waiting for dump time. but nowadays eth and bitcoin prices are on the rise, meaning that it's also pretty good at investing. you can take advantage of this condition to generate instant profits, but still have a high enough risk.