Go to the install directory, then WC

>> Fixes a lot of issues with crashes and not running
Run the Graphic Mode setup and switch the mode from overlay to Direct3D
>> This changes the PLING PLONG midi sounds to proper sound effects.
Edit the WINGCMDR.CFG (rightclick, open as... Notepad)
Change whatever's in there to "v a552"
>> If you use any kind of gamepad / joystick (so you can use hatswitch/dpad and trigger buttons on gamepads)
Edit the dosboxWC.conf (rightclick, open as... Notepad)
change joysticktype=auto to joysticktype=fcs
This way you can actually properly configure your buttons in buttonmapper (if you have changed them before REMOVE the mapper.map file or it will crash)

Ran into all of them, found solutions on this forum and other places, but had a hell of a time finding them. It makes the game better for most people so thought I'd put them all together.

I did the wingcmdr.cfg tweak and now I have sound. Very cool. Thanks!

A very big thank you for putting this all in one place; should be stickied!

About the game pad thing. Do I delete the mapped file completely? Or do I reset it somehow?

So this game doesn't come with INSTALL.EXE which allows you change sound and graphics options?

I suggest cleanly installing it from a fresh download. Maybe you changed things in the dosbox config towards the soundcard?
No idea how dosbox works in linux, what my change does is tell the game to look for a soundblaster card (which dosbox provides by default) instead of a general midi card.

I get Sound Blaster sound without any changes...

Hmmm okay. Well I'm running a freshly-installed copy of WC. I'm using a separate (Linux) copy of DOSBox but I'm telling it to use dosboxWC.conf that came with Wing Commander, so it is using exactly the same settings as GOG specified (and it includes SB16 support). Oh well, I guess later on I'll try it in Windows and see if that makes a difference (I just can't think of why it would).