The secret is using transitions that actually make sense with your video's content, not just throwing them in for the sake of it. On CapCut, you click on the space between two clips in the timeline and a transition icon pops up - then you pick one. But instead of slapping the same transition everywhere, think about what's actually happening: if it's a quick cut like straight-up TikTok, a fade or a subtle slide works way better than those crazy transitions that spin everything around.
Duration makes all the difference. Those super long transitions just feel forced, you know? Keep it somewhere between 200 and 400 milliseconds or so. Oh, and there's something most people don't take advantage of: on CapCut you can actually tweak the transition curve - it's not just apply and done. Go to Effects > Transitions and after you pick one, a graph shows up where you can smooth out the in and out. Play around with the curve instead of leaving it all linear, it looks way more natural.