Sounds like you need to engage in some discipline and some study.
Discipline is the act of sticking to a process or program of work, regardless of the immediate outcomes. When we learn to do anything it is this aspect more than anything else that determines how well we learn something. Some folks call it stick-at-it-ness, others call it grind, it all comes back to work ethic and consistent application.
If the immediate outcomes are poor use that as part of a self-correcting feedback loop (this is called
homeostasis) - explore why the result is poor rather than just rejecting it.
This exploration can take many forms, but a good process to follow is to dissect each part and make minor corrections to one part and observe the results.
Because you are dealing with project files, make sure that you save each new correction with its own unique filename within the project sequence, something along the line of
project-name-date-vsn-999
If you are stuck for
inspiration start by simply picking a chord
progression and then explore the use of just chord tones to create a melody (many composers have used this approach and Aaron Schoenberg recommends it as a first step in creating melody). Remember that rhythmic similarity and variety are both part of making a good melody.
Once you have created your melody using the above process, explore options where you decorate the melody or otherwise transform it. Simple ideas such as playing the note, playing the note above (or below) then playing the note again are common in creating this expanded melodic idea - see
14 tricks to improve your melodies for more ideas.
Creating a melodic line and then repeating it a step below (or above) either in the same scale or as an exact copy is another device that can be used to expand your melodic ideas. Your harmonic progression may shift by the same interval (up or down a step) or by a 4th/5th - the choice provides new depth to your compositional field and provides contrast and interest whilst at the same time the melodic transformation maintains cohesiveness and similarity/familiarity.
Explore ideas such as different scales and maybe even different modes of those scales - they bring new harmonic possibilities as well as new melodic opportunities.
Above all, be prepared to experiment, investigate your failures to understand how to avoid them in the future and document your successes as you progress.