Hi Banj.

There are sooo many variations to a "standard" 12 bar blues. The term "standard" really means nothing. The most basic (might) be:

E//// //// //// E7//// A7//// //// E//// //// B7//// //// E//// B7////

The "crow jane" or "Key to the highway" blues (might be)

E//// B7//// A7//// //// E//// B7//// E//// B7////

A more "complex" blues (might) be

E//// A// A#dim// E// B7// Bm7// E7// A//// A#dim.//// E//// C#7//// F#7//// B7//// E// C#7// F#7// B7//

Infinite variations (and not all 12 bars)

Rick