I sometimes hear other people talk about the difficulties they're having in finishing songs. They create many small musical fragments, ideas which don't progress to full-blown songs. Sooner or later, someone will usually offer advice along the lines of "just finish it. Finishing songs is a skill like any other and it gets easier with experience". To a degree, this is good advice.
Something to keep in mind is the difference between completing a song and completing our progress as artists. Our current song can only be completed to our current level of ability. It's very likely that six months from now, we could come back to it and make significant improvements to it. Hopefully, we will continue to evolve and improve throughout our lives, which means there will always be a point in the future where we could improve the song we're currently working on. Our progress as artists will never be complete.
In order to finish songs, we have to be comfortable in letting go. We have to let go of the expectation that our work will be perfect. It will only be as good as our current level of ability. We have to let go of the thought that soon we will have a better approach to using reverb in our mixes. Our reverb will sound the way we presently know how to use it. We have to let go of our thoughts about our limitations and simply do the best we can do.
In order to finish songs, we need to clearly delineate our "finishing songs" sessions from our "learning how to improve our bass sound" sessions and our "experimenting with compression" sessions. Can songs be finished while doing these things? Sure, but it's less likely than when we make song completion our primary goal. Sessions where we are learning and experimenting are more likely to result in the many small musical fragments many of us end up with. This is totally fine - these fragments are incredibly valuable steps in our learning. There's no need to turn each one into a full-blown song. Only when we have a sufficiently strong idea, or composition, is it likely that we'll be motivated to carry it through to completion. If our focus is on finishing the song rather than on learning or experimenting, we'll be fine.
Finishing songs is a valuable skill to learn and it does improve each time we do it. Our first few songs may progress from beginning to end in a very rudimentary way - instruments drop in and out, instrument levels are fairly static throughout, transitions from one section to another are functional at best. In time, all these aspects and others are refined and our songs become much more nuanced, much richer experiences for our listeners. If we wait until we have "the perfect sixteen bar loop" before finishing a song, we will still have a lot of learning ahead of us in order to create something worth listening to for longer than sixteen bars.
Finish songs, then let them go. There are plenty of great songs ahead of us.
Keep making great music!
Fabian