Apart from getting work the other big worry is finding somewhere to live. Living with other people from oveseas is an option as is sharing with some Japanese. If honing your Japanese language skills is among your priorities I recommend the latter. It can be difficult at times but it's worth a try. I've collected some resources together below. The list isn't exhaustive but I've stuck to my own recommendations plus other options within the budget of an average English teacher. I've skipped anything I felt was overpriced, low quality or seems exploitative. My criteria.
List of links