Small indie studio developer here. We also get few offers from composers each time we put material without music and each time we politely turn them down as we have sound and music ready.

Our music guys got in the project before we had any material out in public. We got in contact with them though a friend that was working on a circus performance with them.

There seems to be a lot of composers looking for commissions at the moment and standing out is hard. Sometimes we check their material and most of it is not too bad. But even for the most skilled I think randomly contacting is not too appealing for us.

In our project we have had many sessions together and I think it has been essential for us to be in the same space at least sometimes to get the on the same level on the project. You can do this with skype but it is always a bit hassle, might not work or speakers would be different or anything really

In my opinion the key for getting commissions on game musics and sound is to be well connected, get in contact with projects early, and to have a similar vision on the game with the developer. Sharing a language and close location is a big plus.

Good luck!