MusicTech have a great tutorial on how to diversify your articulation in Logic Pro.

For the uninitiated, articulations cover a range of playing styles, so that, rather than providing just a single violin sample, a string library will present the principal instrument performed in a variety of ways: often including short and long notes, legato phrasing, pizz, tremolo, trills, col legno and so on.

Use this tutorial to give your MIDI arrangements a wider range of articulation which can add more depth to your compositions and create an advanced piece.

Check it out here!