I am using RDS on amazon with a MySQL interface. My application runs on EC2 nodes and read/update the database, but the number of reads and writes are too many and that reduces performance. Most of the time the number of connections exceed the allowed limit. I was considering using Elasticache to improve performance, however I did not find resources on web, how to configure database to use this effectively. Is this the best way to improve my read/write performance? Any suggestions?
You can't just "turn on" memcache. You need to write code that interacts with memcache, such that your database query results are cached in memcache. Take a look at this users guide -- I think it will give you a good idea for how memcache is used:
http://www.memcachier.com/documentation/memcache-user-guide/