A Teradata DBA should have the following skills:
(a) Sound understanding of Teradata Architecture.
(b) Efficient grasp on Teradata SQL & Advanced SQL.
(c) System Monitoring Knowledge.
(d) Data Modelling Skills.
(e) Script Development/Automation Skills.
(f) Query Optimization knowledge and experience.
(g) Understanding of Optimizer's oriented concepts like Skewness, Spool Usage etc. (Query Explain Plan Understandability).
Besides these above skills, a Teradata DBA should have eloquent communication skills as mostly DBAs need to explain Technical concepts to non-Technical guys like Manager, ETL associates etc.