In conventional blocking languages, you can get a start on parallelizing your programs this way:

  - break program into function calls that match the steps that can happen in parallel

  - wrap the function calls in messages passed over the network
     + i.e. process(thing) -> post(thing)/poll_for_things()

  - split the sender and receiver into different processes

OF COURSE there are big advantages to using a language (Erlang) or a heavyweight framework (map/reduce) designed for concurrency. Rolling your own process-centric concurrency is a different set of tradeoffs, not a panacea. But it's worth considering for some problems.