I somewhat agree and disagree!
I often try to time the market and I've had great success! You just gotta take it slow, sell or buy like 10% at a time. See a dip? Buy some! Still dipping, buy some more!
Bitcoin up 50%? Sell a little, up another 20%? Sell some more!!
Track your averages and start buying/selling when you're above your average by an amount you're happy with :)
Of course, I only do this in projects I truly believe in! Right now, I'm day trading COSS and despite making a 4,000 COSS deficit in my first 2 days, I've made 3,100 back today and rank 13 in their $1,000,000 dollar trading promo!
I made a guide to day trading here where I talk about how I lost 4,000 in 2 days and how I made 3,100 back today!