@bluesheep85 Are these stories you are/were passionate about, or just ideas for the sake of writing ideas? Because while either of those (or any other reasons) are valid, sometimes it's more or less difficult to write when you don't feel particularly passionate about a storyline.
On the other end of the spectrum (this may or may not apply to you) writing something you really enjoy can be even more difficult if you feel stuck or afraid of it not turning out how you hoped.
While there are a million different struggles in writing (these are just two broad parts of the spectrum that can hinder making progress), here is what I hope will be useful advice:
- Are they something you would truly like to finish? Try focusing on them when the passion/mood strikes. Don't push yourself, but be willing to accept that some of your writing will be better than on other days.
- If you enjoy the basic idea/plot behind any of them but don't care for other details, take the framework or general concept and mash it with something you are interested in writing. You can do this with as many partial stories as you like (so long as it doesn't end up with too many plot points to thin it out).
- There's no shame in giving things up sometimes. However, try to keep a draft of your writing stored elsewhere (such as Google Docs), especially if it is a longer piece of writing or holds any value to you.
I can only really give tips based on my limited experience and knowledge, but I hope this helps!