It was said before, but I don’t like to compose or produce only in one genre. There are people who focus, I am not sure I will ever do this, because I feel kind of stuck/not free, if that makes sense? I am not a banker, I want to be an explorer! 
If I need to produce an album in one genre, that’s another story, but the most powerful exercise is to listen to as many genres and tracks out there, and look for something which you find is awesome. I heard super cool ideas from people who actually are not professionals at all. Sometimes it’s just about finding something which you copy to your next cue. A lot of analysing and checking out what’s going on in a piece – what is working well, what is not.
If I compare my “old” stuff with my music today, I realise that I don’t stuck in a stupid loop anymore. Yes I still love cool loops, but I always try to find ways to make the next loop more interesting than that one before. Music is always evolving, it’s never repeating itself, it’s always round-robin and it’s actually full of mistakes… 
As an engineer I started to use almost only Compressors and EQs, which don’t show me the numbers / graphic, so old school channel-strips. The FabFilter EQ shows you really beautiful graphics, but I move the bands as steep as -12dB sometimes, it shows me more and more that I am listening to what’s going on. I used to mix live-shows and you just have to ride the faders all the time, sometimes 20dB to get the feeling for a solo-part, reverb, delay. The same with music. I always remind me to make the progressions more and more interesting…
I am a pianist and had a lot of success in my early career, if I can call it that way…but times has changed and I don’t have a piano anymore, so I don’t practice finger skills, the most technical ideas, which come to my head I still can perform, and if not, I am motivated to record it perfectly, even if it was only 1 from 10. I work with only two octaves at the moment, but if you know how an instrument has to be played, you don’t need all 88 
As an example, this piece is performed with only 2 octaves, I need more, so I re-record over the right hand, and edited after that what I wanted to change. I guess you think I played it live on a 88 keys grand? Nope 
As a composer & musicians in general I think it’s good to stay in “shape” and practice your inner hearing. Intervalls, Chords, Pitches, Scales etc. a good app I found is called “Tone”, learning to get a perfect pitch. For normal people it’s impossible to get one, if you don’t have one, but you can get a good relative pitch, which comes really close. People, like my father, who do have perfect pitch, have huge advantage, but he told me, if he deals with bad tuned instruments, pianos in first place, he easily gets a headache, because his mind is “not used” to hear a “wrong” pitch.
I believe a good exercise in general is to limit your inputs, so just take one instrument, piano, or drum machine, or flute, whatever it is, and try to make a piece of music, which people would listen to actually. Composing melodies and harmony, making textures, sound fx, percussions with it…if anybody knows Trolls from 8Dio, he is a master in these kind of challenges. Sometimes we need to limit ourselves, to start to be creative. Because we have everything in front of us, we offen get stuck, we have too many options.
In general if you want to be overall a better composer and writer, you need to study the instruments, you are writing for. If you know how an instrument should be played, you will instantly see, how your productions transform into much better scores. At some point you won’t mess around with articulations which still don’t work well, when played back. You just leave them out, and use other samples, articulations etc.