Troubleshoot & resolve video buffering

Seek internet video expert/specialist familiar with FLV to troubleshoot repetitive video buffering delays of videos on newly-created CMS site. Currently use JW Player, version 4.15, all videos set to auto-play, accessibility plugin (to show captions (from SRT files). CMS is currently on shared host server (Linux Business package – shared, 250 gb hard drive, 10 mb RAM). Need to track down and identify cause of buffering problem (i.e. server, player, encoding, file size, etc), and how to minimize delays without costly third party solutions.