I usually try different Point Cloud Density settings. I had a mountainous forested scene with a flat grassy valley. Ultra High might look great in valleys, but then poorly in the dense forests. High may have few gaps, but then not as dense points. Then I weigh the differences and see which one I prefer more. Or split the project up and do the trees separately, then import them. For flat areas, Ultra High has worked great, then I get a super high quality DTM/DSM.