From Chris Mortika  on Paizo Forums

If there are NPC archers holding actions, waiting for you, the wizard, to start casting so they can disrupt your spell: use your move action to “Gesture and chant, like I’m casting a spell.” Attacks, hits, damage. Then your standard action is “Cast the spell.”. [This might require a Bluff check vs. Sense Motive, but it’s perfect for Sorcerers. Note that Bluff is technically a standard action, but your DM might let you get away with it if you don’t abuse it.]

From DeZrog (original content)

The most powerful L1 spell is Silent Image. Need to obscure enemy archers? Illusionary wall. Distraction? Illusion of enemy sneaking up on your target. Need to hide or ambush? Illusionary cliff. Combine with Ghost Sound (L0 cantrip) for better effect.

Spam Detect Magic all the time. Tell the DM your character is just really curious.