This is good advice imo.
Also know what you are buying. I never trade cyclicals with a 'net free' strategy. Examples are AMD and MU. Semis go through cycles, and this is known. You can make mega profits when they have an upswing, but they're gonna come back down and then back up. You can make a lot of good money playing these. Buy low, sell high. Same with others like O&G...use and abuse those tickers over and over.
Then if you're in taxable accounts you have to consider those tax implications. So you're selling profits and paying taxes on the gains when those gains that you are marginalizing could keep compounding and putting off taxes into the future. I rarely trade shares in my taxable brokerage account. Either buy something safer with good upside like AMZN and plan to hold forever, invest in a SPY/IVV/QQQ/IWM mix and reinvest dividends (or sock away the cash), or trade options. Options are the juice, and cash is king so always have some ready to go in case of a meltdown. If I make a net killing on options in a calendar year, I'm more than happy to pay Uncle Sam for that. The rest is just responsible investing with liquid money that you can tap into if you ever get into a bind.
My swing trades with shares are almost always in 401k brokerage link (Fidelity) or Roth IRA. I also have all options capabilities in Roth IRA and do covered calls. All of this with zero taxes paid now! It's also where most people have more capital. I've read a lot about financial advisors saying to never ever ever invest or trade individual stocks in retirement accounts. That is very true for almost all people, but if you figure out how to do it, you can absolutely kill it due to lack of tax implications.