How to set strategic buy/sell orders so you don't go crazy

If I correctly identify the bottom before an upswing and buy, then I see the price spike, that is all great, BUT...how do I know WHEN to sell? More specifically, what if I go to sleep and wake up 8 hours later to see the spike happened 2 hours after I went to bed and started dropping again before I woke up?

I guess the way to avoid this is to set up sell orders. But at what price? Do I guess how high it'll go, e.g. I predict it'll rise 10% so I set a sell order for 1.1*[price at which I bought]?

Also, in Bittrex, I know I can put a stop order so that once the price does start dropping below what I bought it for, I can begin selling (and wait to buy again later). But what if I set a sell for, again, 1.1[price at which I bought], then the prices DO rise but they only go up to 9%...I take no profit and then sell it back near to where I bought it.

Is there any solution to this besides, uh, never sleeping and staring at the markets?

I have bought four coins so far (negligible amounts; I'm obviously new to this) and it seems a little impractical to constantly wake up and rush to check charts.

I know professional traders have a strategy whereby they set buy/sell orders and/or alerts. But how do they do it?

Thanks for the pointers, I really appreciate it!

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P.S. If you have any links, videos, or good old books to recommend where this is specifically explained, I'd love to know about them!