Drupal 7: pull out just the Twitter job as its own Cron job so that we could run it every minute
There are a couple of different cron managers available, personally I use Elysia Cron


  Elysia Cron extends Drupal standard cron, allowing a fine grain control over each task and several ways to add custom cron jobs to your site.


But there's also Ultimate Cron which I understand is very good too


  Runs cron jobs individually in parallel using configurable rules, pool management and load balancing.


Either of those will let you isolate the Twitter cron job to be run more frequently than the normal one.