Inadequate job descriptions. The job descriptions that drove the hiring process focused solely on experience and skills rather than company expectations for the position.
Superficial interviewing. The hiring process did not put candidates under the magnifying glass, verify claims or check facts.
Inappropriate prerequisites used too early in the selection process. An over-emphasis on specific education, technical skills, and industry experience screened out qualified candidates.
Snap judgment. Hiring teams relied too heavily on first impressions to make final hiring decisions.
Historical bias. Hiring teams used only past performance to predict future results.
Performance bias. Hiring team failed to understand that interview behavior and job performance are two different things, which resulted in making an offer to the "best actor," not the best candidate.
Fishing in shallow waters. Structuring the search to attract only the bottom third aggressive candidates; not actively seeking out selective "sleeper" candidates.
Failure to probe for core success factors. Not looking for evidence of the five best predictors of long-term success — self-motivation, leadership, comparable past performance, job-specific problem solving and adaptability.
Ignoring top candidate's needs. Not understanding what motivates top talent to take a job.
Desperation hiring. Not budgeting enough time for the search, resulting in shallow sourcing and superficial interviews.

Deutsch and Remillard, also noted these other pitfalls:

Ignoring cultural mismatches
Not physically preparing (reception, waiting area, greeting, etc.) for successful interviews
Failure to create compelling marketing campaigns to attract top talent to open positions
Passive sourcing (waiting for resumes to come in rather than actively pursuing sleeper and selective candidates)
Lack of preparation for interviews; no written questions
Failure to evaluate candidates against an objective definition of success

To find steps for successful hiring look at these Vistage articles on Building a Hiring System or download this free report on Hiring Best Practices.