Glyphs are commonly used to augment a character's spells and abilities. In the case of an Elemental shaman, The glyphs that are considered useful are those that adjust the properties of their offensive spells to suit their preferences for ranged combat.

The following glyphs are considered by me to be the best for any PvP situation.

1.) Glyph of Chain Lightning. This makes your Chain Lightning spell hit one extra target, rounding up to 4 targets total. The damage reduction applies to the 4th target, but any damage dealt is good damage, plus it enables you to strike more enemies and harass them at a distance when both sides are on a deadlock.

2.) Glyph of Thunder.. Your Thunderstorm spell cooldown will now be reduced by 10 seconds. Useful for when you're surrounded by enemies and you need some space to maneuver, which happens quite often in PvP.

3.) Glyph of Lava. Increases your Lava Burst spell damage by 10%. Widely considered to be the best glyph for Elemental shamans in PvE and PvP, this glyph increases the damage of what is most likely to be your most used spell in PvP, considering its spell cast times and its damage.

4.) Glyph of Shocking. Reduces your global cooldown timings for Shock spells by 1 second. This, combined with the talents for reducing the cooldowns still further, is ideal for frequent use of the Shock spells, like Frost Shock for instance.

5.) Glyph of Lightning Bolt. Increases the damage of your Lightning Bolt spell by 4%. As your Lightning Bolts already have a significant damage output among all your spells, this is a good Glyph to choose if you prefer unloading this spell at a distance while staying still.