Here are some guides our players have made for the PC version, they're most likely useful here too. And if you make a guide of your own or know one you want to be included in this list, let us know.
Singleplayer:
Galdus' Singleplayer Manual:
http://forums.taleworlds.com/index.php/topic,113493.0.html
Singleplayer Q&A Thread:
http://forums.taleworlds.com/index.php/topic,120858.0.html
Multiplayer:
Corsair's Duelling Guide:
http://forums.taleworlds.com/index.php/topic,174526.0.html
CrimsonShroud's Archer's Guide:
http://forums.taleworlds.com/index.php/topic,104123.0.html
Reapy's Mount & Blade Warband Infantry Primer:
http://forums.taleworlds.com/index.php/topic,87133.0.html
Nahkuri's Gentlemen's guide to dueling:
http://forums.taleworlds.com/index.php/topic,104175.0.html
What is Chamber Blocking?
http://forums.taleworlds.com/index.php/topic,243074.0.html
Multiplayer Q&A Thread
http://forums.taleworlds.com/index.php/topic,200604.0.html
Advanced Warband Mechanics Guide
http://forums.taleworlds.com/index.php/topic,255546.0.html
Windle's Infantry Tutorials
http://forums.taleworlds.com/index.php/topic,340177.0.html
The Art of Fighting in Warband
https://forums.taleworlds.com/index.php/topic,345313.0.html
Singleplayer:
Galdus' Singleplayer Manual:
http://forums.taleworlds.com/index.php/topic,113493.0.html
Singleplayer Q&A Thread:
http://forums.taleworlds.com/index.php/topic,120858.0.html
Multiplayer:
Corsair's Duelling Guide:
http://forums.taleworlds.com/index.php/topic,174526.0.html
CrimsonShroud's Archer's Guide:
http://forums.taleworlds.com/index.php/topic,104123.0.html
Reapy's Mount & Blade Warband Infantry Primer:
http://forums.taleworlds.com/index.php/topic,87133.0.html
Nahkuri's Gentlemen's guide to dueling:
http://forums.taleworlds.com/index.php/topic,104175.0.html
What is Chamber Blocking?
http://forums.taleworlds.com/index.php/topic,243074.0.html
Multiplayer Q&A Thread
http://forums.taleworlds.com/index.php/topic,200604.0.html
Advanced Warband Mechanics Guide
http://forums.taleworlds.com/index.php/topic,255546.0.html
Windle's Infantry Tutorials
http://forums.taleworlds.com/index.php/topic,340177.0.html
The Art of Fighting in Warband
https://forums.taleworlds.com/index.php/topic,345313.0.html