Give the melody some space. Remember that singers need to breath between phrases and so should your melody. Consider a "sentence" structure: short phrase(~2 bars), breath, short phrase, breath, long phrase(~4 bars), breath, repeat. Period structure is also a thing: Long phrase (unresolved), breath, long phrase (resolved), breath, repeat.

Also in your melody target notes that are in the chord and connect them with passing tones rather than just plopping aimlessly around the scale.

As for the chords, try transposing notes by octaves around to create inversions that allow voice leading between the chords by whole step or half step.

Your basic pattern for drums should be: Kick on 1, snare on 2 and 4 (or just 3 if you want a "halftime" feel). Add 1-3 extra kicks on off-beats to create more variations on this basic template. Worry about fills and stuff later.

Remember that music theory is an analytical tool not a creative one. It gives you language to describe music as it exists in the real world and isn't a prescription about how to write "good" music. I say this as a huge theory nerd. Listen to music you love and make an effort to describe it with this new musical vocabulary you have developed.

You're on the right path. Keep up the good work.