Dynamic Shaping of Long Notes
Hardly any musician in an orchestra will play a long note with a static dynamic as samples do. Even if you don’t write in any dynamics or hairpins, the musicians will shape sustaining notes dynamically on their own. It’s usually very obvious on the end of phrases where the final long note always gets a decrescendo. But also depending on the context long sustaining notes within a phrase will get more or less dynamic shaping without indicating it which is big part of why real recordings sound so much more organic and lively than sample productions. So there are several things you should take care of on long notes in general. Firstly, support the natural dynamic shaping. Sustaining long notes becomes boring quickly so actually writing in a dynamic shaping helps making these notes more interesting. Very popular are for example on long brass notes to hit them loud, drop instantly to piano and crescendo back up to forte. So don’t be shy to use hairpins in your music also within phrases (again, as usual there is also a chance of overdoing this, so keep it reasonable). The other thing is to transfer this knowledge to your midi productions. Don’t just let sustaining notes sit there but make sure to give them a natural and interesting dynamic shape. So the modwheel or C11 should become a standard tool in your mockup.