I've 'started' but not really advanced about 5 conlangs. (I've also created 4 concultures. :D)
I soemtimes find a piece of paper with sounds on them. The one I'm currently working on is my favorite, and will probably be a really eprsonal one. I'm not even attempting to make it "natural". It's got my favorite sounds (clicks! and approximates and fricatives and clicks! did i say clicks?), and it makes a lot of weird distinctions (different pronouns on whether it's day or night, or in between, or if you're narrating as opposd to normal talking.)