Start at fret
Include open strings
Tuning à la:
Mandolin
Mandolin

Ukulele
Ukulele

Banjo
Banjo

Pipa
Pipa

Bouzouki
Bouzouki

Bass
Bass

 
Simple chords, not necessarily using all notes of the chord
More complicated but usually better sounding. Repeat note on triads

All chords are calculated and therefore may not be really playable!
Special custom tuning: Balalaika
(okay, a Balalaika just has 3 strings... Just forget about one of the E-Strings!)