Probably the most useful tip to finish with is that the Spark-users' mailing list is an excellent source of up-to-date information about other people's experiences with Spark. You can subscribe to https://groups.google.com/forum/?fromgroups#!forum/spark-users (soon to be http://mail-archives.apache.org/mod_mbox/incubator-spark-user/) as well as search the archives to see if other people have run into similar problems as you have.