Your best bet will be to contact large yacht clubs at your source and destinations - they often have people advertising for crew. Ther are also lots of websites for this purpose
eg
www.crewseekers.co.uk,
www.yachtcrewregister.com
As mentioned this is likely to end up costing you quite a bit unless you have some sailing or other useful skills that will be of benefit. Another option is through a yacht delivery company, which won't cots you anything but they will also want some useful skills.