I'm bored, so I thought I'd throw you all a favor on how to make your sampled acoustic instruments sound more realistic on music studio software.
All keyboard instruments play the same way, so to make them sound accurate and beliveable you have to understand what is possible. A keyboardist can play up to ten notes at once (though this is very rare) and can hold notes on using the suspension pedal. Most of the time, however, the bass (left hand) of a keyboardist caps at 2 notes, while the treble (right) hand plays up to three at once.
The furthest the average pianist hand can spread is 1 octave + 1 or 2 notes depending on age and skill. Its very hard to play fast like this, so if you have a hand for the pianist hold two notes at such a large distance, consider having it so they hold the notes rather than change them quickly.
It isn't unusual for the left and right hands to merge what they play together like broken chords. Use this with pedal, and you get a very awesome sound.
Also try the adding of some glissandos, which are those things where the pianist runs his hand up the keyboard hitting all the white notes.
All of the main string instruments can be played in two ways. They can be either bowed or plucked (pizzacato). Use these two effects widely in the song for extra diversity.
When being plucked, a stringed instrument can play one note at a time, and not very quickly. If you are having a pizz section in your strings, try to keep the notes longer than a quaver each, or put rests between them.
When bowing, a stringed instrument can play two notes at once. For realism, if you have this, try not to make the difference between the two notes more than one octave.
Strings are an instrument that you really, really need more than one sample set for, as there are so many different way they can sound. For best effect, you will need at least, Pizzacato strings, Staccato (sharp) strings and Legato (smooth) strings. Try having the deeper strings playing legato while the higher strings play the top.
All strings can slide and pitch bend.
In order from lowest pitched to highest, it goes Double Bass, Cello, Viola, Violin. Make sure to pan them out to give it a realistic spread.
Brass instruments are a bit more straight foward to strings. If you have french horns, try to get two sample sets for forté (loud) and piano (soft). There is a HUGE difference between the two. Trumpets are also easy, as they only play one note at a time each, but trumpet sections normally have up to 4 trumpets, so don't be afraid to use chords. Trombones can slide and pitch bend.
I'd recommend against using muted brass instruments in orchesteral pieces, though if you want a jazzy touch to somthing else, go ahead.
For all Reed/woodwind, you will want two sample sets, loud and soft. Also, it helps if you have a tremlo sample set for flutes and piccalos, as these effects are used extensively in orchesteral music. Flutes always sound best solo on melody, and clarinets work very well playing duet backing to said flutes. Have a basson playing the same line as your double bass/cello and you've got a lovely layered sound.
Glockenspiels are awesome. They normally can play three notes at once, (two with left hand, one with right) and if you layer them with your melody, it adds an extra contrast between that and the rest of your orchestera. Don't overuse it though, or you end up with a music box.
Consider having some tubular bells, they sound like church bells, and are tuned as such. In the very loud layered sections of music, they can add extra depth.
Always have a nice snare sample handy, and give it some reverb effect too. The piercing sound of a snare helps amplify the beat in your music to give it another excellent edge.
Timpanis are very useful, but remember that if you include them, they can only play three notes for the whole song. These are usually the key notes of the key of the piece and realitive minor with one in-between. Timpanis have a very small range, just over one octave, and you should always put a reverb on them.
Well, I'm bored of typing now, So I bid thee farewell.