Incomplete Songs

I do mostly metal but its more on the pop side than the extreme metal side. Some passages are death metal but there is also a lot of clean voices and synths effects. No horns but some synth string parts yes. I think the only trick that can help me here is from what Billy M said is track more ideas and variants every passages and work with those in the arrangement. Yes it's a lot of work to build songs alone or almost alone. I'm not a pro but I'm to a point where leting somebody else do the work of mixing or composing is often unsatisfactory. Even if they have more talent. I guess I'll just have to kick myself in the butt harder and accept that arrangements are a long and hard process for me....