Hello, welcome to LMMS!
Over all, pretty decent for a first track!
A few things to suggest:
The sounds are very dirty and unworked with, use the 'Equalizer' effect (EQ for short - learn about it here:
https://www.youtube.com/watch?v=2oH4YcpyWSs) - this is an effect you can apply on any of your instruments, if you aren't familiar with LMMS effects, watch the first minute of this video (
https://www.youtube.com/watch?v=BI3KAoQ2Eho).
Another thing, the track doesn't have that much depth. Usually to have depth in a track, you have to have a bass, chords, drums, a lead and some sort of high frequency layer (usually your leads, hi-hats, snares and claps do the job). You have a bass, although you could work on the low layer still. Add some chords in the background - maybe take that synth string-like sound, turn it into a chord and turn the volume down on it a little.
Also, use more 'Reverb' effect - don't underestimate this, it adds depth - reverb isn't too complicated, I recommend just messing around with different reverbs in LMMS and messing around with the knobs in them to see what they all sound like and do.
Lastly, layer your sounds more (this means putting a few different sounds together to make a new sound) - this makes them have more depth often even without complicated effects, just listen to these two snares, one is layered and the other isn't:
https://soundcloud.com/eugene-levchenko ... es-example .Very simple, but effective.
I know that's a lot, but just slowly work through everything and you'll get better!