I personally have success both with online and a local TA.
If I was use online I would probably try Vacations-To-Go.
then a local TA or one close to yours town/city.
Either way use an agent that has cruise experience & training (CLIA or equivalent)
All can sell but some have the experience of cruising .
Any agent should ask some important questions
1 - type of activities they do (very active or a coach potato type)
2- age group
3 - budget (very important)