Swing trading in short form is holding a number of stocks that you're very familiar with. If one of those stocks moves one way or the other by acting uncharacteristically, over reacting to news, moving more than it should, etc you buy the dip and sell the surge. Whenever it 'swings' off of the expected price line you would sell a portion if it's going too far up and buy if it goes too far down.Those guide rails can be described as an envelope of a high and a bottom. You would expect the stock you're following to live inside that envelope and if it goes off the highside you sell (or short if you're so inclined), if it drops below the lowside you buy. You can have a complicated formula that describes that envelope, it could be 2% above and below the sma, you might adjust that up or down expecting more market wide news, whatever strategy you have.The key part here is you're making informed purchases on stocks in accordance to your own rules. By following this methodology when you find something isn't working you adjust the rules to fix it. As you dial in and perfect your strategy you get reliable gains.Conversely if you are making daily decisions based on tips or memes or what's hot; regardless of the outcome you can't repeat it and can't explain what went right or wrong except that it didn't move the way you expected.
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