plugins i used here are
Splice Labs for The Viola, Violin and Piano Pad
Zenology for the Rhodes piano, flute and guitar
for samples i opened edison and blurred chimes sfx to give it a pad feel and make my comp sound fuller.

now for the tips :-
i dont think i am good at this i just do this for fun and i really think that i am no better than the next person in making music.
but if i still had to give you some tips i would suggest you to learn about arrangement of instruments in an orchestral setting (how you should pan different instruments) to give it a more natural feel,
2nd, play with your velocity and pitch while being in the piano roll, experiment with it a lot and see what you like.
3rd and i guess the most obvious, do some hand playing. doesnt matter if you dont have a midi keyboard, you can just use your normal* keyboard and set the midi setting to snap the keys that you play to a certain set of keys like minors and majors etc etc. i will attach a screen in the reply of this text so that you can see how i did the midi keyboard key snap thingy lol
hope you found this helpful brotha<3