Hum ....

Well ...
Let's start positively, there's the melody, the bassline (well kinda), and the rythm which unfortunately stops right after it began. They all fit together. The idea of a MK loop is actually good. You offer variation beginning around 0:23, so the listener don't get bored too quickly.

Now, there is much room. Let's start by the samples. The samples, man, THE SAMPLES ! Use a "saw" effect of your string thingy, it's too ... let's say brutal ! It's not soft enough. After listening 2 times to your loop, even if my volume was relatively low, my ears were hurting ! Choose your samples (or instruments, if you prefer) CAREFULLY !
That being said, you need to add stuff. It's not "filled" enough. What you could do, is adding a synth string to make the chords.
For example, (while using FL Studio) if you want a classical approach, choose Sytrus/Synthstrings/ Violon Ensemble 2. Then, add the chords in the piano roll, around C4, an octave below the normal C (C5), and lower the volume a bit.
If you want a more techno approach, choose Sytrus/SynthStrings/ Basic. That you can keep around C5, but still , lower the volume a bit.

Then add some rythm. You can do this with the Kick, Clap, Hat and snare already given, OR you try to make something using a drum plugin named FPC (Channels/Add one/ FPC).

That's just suggestion, there's much more you could do, but keep in mind that for a successful song, there SHOULD be 4 things :
- Melody
- Bassline
- Rythm
- Chords (or Arpeggios, denpending on the type of music)

I hope you'll considerate my advices !
Good luck if your next composition !