fundamentally there is only the ear to rely on;
you need to learn what instruments are what in terms of the acoustic ones (orchestral and pop music instruments including guitars of all ilk),
what fx have been added to certain instruments (only way is to either look up the performer or observe live videos, at least to begin with) - I can recognise most of the Boss foot pedals simply from having used most of them at the start of the 80's;
then hunt and peck for the basic synth that might have been used or at least scan and span your sample library to know what is where - understanding basic subtractive synthesis doesn't hurt your process as you can identify waveform, adsr and filter settings if you have done enough basic work with this type of synthesis (been doing it since 1978 myself)
i.e. nothing beats experience and focused listening - if you don't what a sound is ask a question here, lo\ts of folks who are more than happy to have a listen and tell you what it could be or how to create for yourself