Writing “For Samples”
Even with all the advancement in sampling technology, you unfortunately still need to write “for samples” nowadays. This means that you need to keep the strengths and weaknesses of your samples in the back of your mind and strategically use or avoid them. Trying to mock-up pieces that have been written with a real orchestra in mind will most likely be a nightmare to mock-up convincingly. Some things that sound brilliant with live instruments will sound horrible with samples. So write strategically for your samples if the end result will not be a live recording and you need to deliver a convincing result.
The biggest issue is to develop an understanding and feeling for these two worlds. Many composers get stuck in believing that their samples set the benchmark for what works and what doesn’t with live players. This often results in a very limited instrumental variety. Keep studying scores and listening to real recordings to spot things that work very well with live players but you couldn’t do with samples.