For the "genuine" shabby-chic Irish pub look.................
Lightly sand to get surface dust and grime off.
1 or 2 coats of ordinary emulsion
When dry, rub with fine sandpaper or coarse wire wool. Pick a few "wear" spots and concentrate on them until the emulsion comes right off - back to the wood.
Thin some polyurethane varnish 50/50 with white spirit, and apply liberally - let it accumulate in ledges to give a good brown colour.
Practise on something first.
The look will be that of something that has survived a hundred pub fights, and the nicotine from a million fags.
If you want to "sand back" to a different colour from wood, then emulsion in any background colour... then apply the top colour (the one to rub back)