The best thing you can do is ask your board house. Tweaking can depend on your design and board house. But generally, you want:
Copper files for all layers, like gtl and gbl, but also inner layers (like g1 and g2 for 2 inner layers)
Soldermask files for top/bottom layers (gts and gbs - gerber top/bottom soldermask). These are actually negatives so you specify which parts should be cut.
Silkscreen files (gto and gbo - gerber top/bottom overlay)
Additionally if you want a paste stencil you also need to export paste files (like gtp and gbp)
Then it's usual to supply a board outline separately, which can be on a mechanical layer in your CAD file. Most board houses also like if you plot the board outline on all gerbers, so they can make sure the alignment between gerbers is correct.
If you're taking your design in production, ask the fab house if they will panelize the board for you.
How you actually export the right data is up to your CAD package. Generally you can find some plot options which then asks which layers you want to export, and which layers you want to export to all gerbers.
Additionally you want to check if you export in imperial or metric units. I generally choose between the 2 depending on what (dominant) grid I made the PCB on. For SMT this is usually mm.
However if you export with many digits of precision, it probably doesn't matter that much.
Edit:
You also need NC drill files. These specify which holes need to be drilled. Usually they are exported seperately.