I've only just started glancing at elasticsearch-head, but this is a utility you must have for ElasticSearch. A few screen shots, though I must say I don't yet understand half of what's going on here...
The overview page, where I see the state of my ElasticSearch clusters, nodes, replicas, shards, etc. and the indices they contain. (A bit boring on my laptop... :-) Tons of information here.
Structured queries allow me to point and click, choose fields I want to add to my query, hit a button and BOOM: results.
Perform queries, view results as tables or JSON, validate queries, etc.