Commercial product like Ableton are as difficult to use as lmms is, maybe more. So after follow tutorials on about to use lmms like cubician ones (
https://youtu.be/4dYxV3tqTUc), then you need to focus on your main melody, try do it with piano and then changing instrument, then add drums (simple ones in house style like every 1/4), and then bass, you can use the notes of your melody, or try playing it on your melody and then write it down in piano-roll. Also don't give up, remember that first things are always awful, i spent three years on lmms and my music is now at a good level but not as a pro level like great artists.
So this is the base for a melody, but learning scales and tonalities could help a lot, or at least learn chords, you can do all with them. So this should be a good base to make music.
Another good technique is layering, that is like playing the same melody with two leads at the same time, to get a cooler lead.
In the end remember that the first pieces aren't good, but the next song you do is always better than the one before, and so is also with the future ones, until you become good. Year after year you will learn new techniques, and you will improve your melodies, be sure
Anyway i don't know if i get to the problem, but i hope i helped. Also remember that until you can't do a good (not great) song with lmms, you can't do it also with ableton and others commercial products (that also cost a lot). Like ableton is the pro daw, but it's really difficult to learn, and the only one commercial daw i tried that was more intuitive was fl studio, but you can do most of things in lmms. At the beginning use preset, i use it most, too, because learn sound design is difficult, and so do it later when you will have improved your music skills.
Last thing if you're still using LMMS 1.1.3. download 1.2.0 Beta, is cooler, and has new feature like a really cool native equalizer
P.S Also remember i'm speaking about EDM and house mostly. Also cubician tutorials, tells you how to do sidechain that is a nice feature for beginner (and a lot of famous people use it, too)
