From the three classes in the Tome of magic the other two get all of the attention. From the big
football combat star Binder class, to the weak willed short bus ridding Truenamer class that everyone tries to fix, the shadowcaster is forgotten class that gets mentioned but rarely get any help. The little Dark templated sheep of the family.
The unofficial unofficial errata by the designer post
here help to make the class actually playable, if still quite underpowered.
They can get a Dark templated familiar though Shadow familiar feat, so Prime32's mount handbook should help in that regards. Even more so for the Master of Shadow's shadow servant.
With the way the shadow caster casts the their mysteries as SLA's at certain levels, the spellthieves steal SLA could be put to use.
You can flicker in response to someone getting in melee attack range, making a lot of melee attacks miss. You can Bolster to get an actually useful about of temp HP.
With early entry for the Noctumancer, then Mystic Theurge you can get 19th shadow casting, and 17 wizard casting, but this only means wizards make everything better.
You any tricks you can find to help out this mediocre class?