I use foxtrot canceling like it's bread and butter. For those of you guys struggling, you won't get this down in a 3 hour training session, or even a good day or two. It took me a week of consistent foxtrot training with Sammy to get it down. When you input the initial dash, release the stick as soon as you can so that the next inputs for the foxtrot are easier, and have no chance of interruption from your original input. If you really wanna practice this, start using Captain Falcon, Marth, and Little Mac, as they have amazing foxtrots that are relatively easy to input compared to Samus.
When you get this down, you'll realize the plethora of options that come out of this. I use it virtually everywhere as a bait and punish option, if you've watched my gameplay videos you'd see it come out. Samus has a really good foxtrot believe it or not, it may seem slow, but it covers much more distance than you realize, and is significantly faster than other characters (For example, Sheik, or Rosa). Just keep practicing it guys, it'll take a while, but it's a key movement option for Samus. Tech in this game is much more important and should be used like bread and butter for bad characters like Sammy.