What can a spellcaster do when their magic is canceled out somehow?

Possible ways of canceling a spellcaster's magic:
--Forcing Silent or Still spells by making verbal and/or somatic components impossible
--Counterspelling
--Using magic-immune creatures
--Using an antimagic field

What strategies should a spellcaster use against these tactics?

Magic-immune creatures: Spells without spell resistance allowed will still work.
Antimagic Field or Silence: Get out of range.
Counterspelling: Cast spells from hiding or while invisible so they can't see you to identify the spell.

And always having a silent or stilled (or both) escape spell available...

Am I missing stuff here?