I'm assuming that you've logged into Bluemix via the CloudFoundry command line interface
Step #1: Go to the Meteor application directory on your local machine
Step #2: Add .cfignore file to ignore downloaded packages associated with this app (This will be downloaded again while deploying Meteor, so no need to upload them).
echo ".meteor/local" >> ./.cfignore
Step #3: Create a MongoLab service (specifically go for MongoLab and not any other MongoDB provider). At the time of this writing Bluemix did not have a MongoLab instance in Europe (eu-gb) so you will probably be able to deploy your Meteor app only in North America (US-South).
cf create-service mongolab sandbox <unique-name-for-mongolab-service>
Step #4: Bind the created Mongolab service to this application
cf bind-service <mongolab-service-name> <bluemix-app-name>
Step #5: Push the app with Ben Cox's Meteor buildpack for Bluemix.
cf push <bluemix-app-name> -b https://github.com/ind1go/bluemix-buildpack-meteor.git
That's it. Wait for the push to succeed, you should see your Meteor application up an running on Bluemix!