So , this question bothers me a lot ... what are some standard voicings for different types of chords on piano.What are the most frequent techniques used for distribution of notes among orchestral string, brass and woodwind instruments.I know very little about such stuff (e.g. writing double bass and cello in octaves, writing violins in thirds etc) but want to expand my knowledge to have a better understanding of orchestral instruments and chords.Sorry if I sound stupid ... I have never attended any music classes,the only music theory things I know are from Youtube videos

 

That's all any of us know~ Really, I haven't either. But, I found that spacing chords throughout the octaves works well when using different instruments/sections. And, you should try different voicings to get your desired feeling in the music. After all, that's what you are sharing with everyone through your music - "your feeling."

 

A good video to start with

 

There is no such thing as standard voicing. Even very famous composers have written very stupid or unplayable stuff (or the instrument has changed over the centuries, so the score doesn't translate to modern orchestra) that has to be edited before actual performance.

You are probably writing with sample libraries - these don't give very good impression of orchestral instruments' limitations and capabilities.
(If you write a typical trailer/hybrid brass part to a real orchestra, you will probably kill someone and it will sound different, because of loudness balance issues.)

Honestly, instrumentation and orchestration for real orchestra takes many years to learn and master, but you need none of this knowledge to just play with the orchestral vsts, working out whatever sounds good on your soundset; it's not like the knowledge of real orchestral techniques translates well to DAW music. Composing shitty new-age/trailer/hybrid/electro-orchestral music is easy, but making a realistic mock-up of a real symphony or tone poem can be incredibly hard task, because of all details and automations that have to be performed.

If you want to imitate a particular school of composition (style), study it (score reading). Don't expect tips that translate to every possible way to compose for big ensemble.

Type "orchestration" in the amazon search bar and you will find many (expensive) books. Good luck.