When I record vocals, the rest of the mix is generally done. In other words, I record and mix in the vocals last. There might be a few tweaks to the other instruments after the vocals go in but nothing major. I like singing to the finished, full band mix.

Your vocal should set comfortably in with the existing mix of instruments. Bob mentioned compression. You absolutely need to know how it works, what it does, and also learn to use it effectively and not to the point where it damages the mix by having too much compression.

Another "cure" for thin weak vocals is to use layering or doubling along with the proper levels of compression. That's possibly another thread in itself.

And don't forget to use compression and gain riding on the instruments. They need to pretty much maintain a relatively consistent level in the mix... especially the rhythm section.... bass, drums, and acoustic guitars...etc.

You can find my music at:
www.herbhartley.com
Add nothing that adds nothing to the music.
You can make excuses or you can make progress but not both.

The magic you are looking for is in the work you are avoiding.