What advice can you give to Referees on the correct application of Obstruction calls (Rule 10.02) and Baseline violations (Rule 10.01)?

Remember that the baseline is not always a straight line between two bases, but is determined by the route the runner takes.
A fielder possessing or actively receiving the ball cannot be guilty of Obstruction.
Neither type of infraction immediately ends the play, though they can be called after the conclusion of the play.
Runners that choose to advance beyond an awarded base while the play is still in progress do so at their own risk.
Refs may award an additional base beyond the one the runner is obstructed from reaching, if the Ref feels that deliberate and unsportsmanlike Obstruction alone has prevented an uncontested advance.