Your blade must be very sharp and have lots of teeth too. I use a Freud 80 tooth carbide trim blade and masking tape. I like the idea of scribing first with a razor or x-acto knife, especially on the off side of the cut. You want to slice the wood fibers, not rip them out.
If you use a table saw as I do, it helps to make a sled that rides in the mitre guage slot. Then you can shim and lightly clamp the stock to get a square cut at the exact pitch you desire.
Power saw blades must have no runout in order to get a clean cut. Years back, a buddy bought a used radial arm saw that splintered every cut, even with good new blades. We found that the previous owner must have allowed the saw to slam into the table when he loosened it to adjust the angle. The motor shaft was bent at the blade end which gave a slight wobble at the cutting edge. It was only about .015" as I recall, but was enough to cause tearout. Fine for framing, but useless for finish work.
