How to group drush command sets together in sequence? For example, when installing a drupal site, there are 3 sets of commands:

drush dl drupal-7.x

drush site-install standard --account-name=admin --account-pass=admin --db- url=mysql://YourMySQLUser:RandomPassword@localhost/YourMySQLDatabase

drush make example.make


Is there a way to group these 3 tasks and have drush do them one by one without having the user do it 3 times?
There are quite a few, I tend to use a shell script, but you can create your own drush command: 
http://www.sitepoint.com/drupal-create-drush-command/

Here is an example of how I would do this with a shell script (mac / linux).

#!/bin/sh

# Default parameters to use.
version="7"
profile="standard"
user="admin"
pass="admin"
mysql_user="YourMySQLUser"
mysql_pass="RandomPassword"
mysql_host="localhost"
mysql_db="YourMySQLDatabase"
makefile="example.make"

# Collect parameters from the command line to override defaults.
for args in "$@"
do
  # Get the drupal install version.
  if [[ ${args:0:10} == '--version=' ]]
  then
    version=${args:10}
  fi

  # Get the installation profile
  if [[ ${args:0:10} == '--profile=' ]]
  then
    profile=${args:10}
  fi

  # User name to give the drupal admin user account.
  if [[ ${args:0:7} == '--user=' ]]
  then
    user=${args:7}
  fi

  # Password to give the drupal admin user account.
  if [[ ${args:0:7} == '--pass=' ]]
  then
    pass=${args:7}
  fi

  # Mysql username
  if [[ ${args:0:13} == '--mysql-user=' ]]
  then
    mysql_user=${args:13}
  fi

  # Mysql password
  if [[ ${args:0:13} == '--mysql-pass=' ]]
  then
    mysql_pass=${args:13}
  fi

  # Mysql host
  if [[ ${args:0:13} == '--mysql-host=' ]]
  then
    mysql_host=${args:13}
  fi

  # Mysql db
  if [[ ${args:0:11} == '--mysql-db=' ]]
  then
    mysql_db=${args:11}
  fi

  # Drush make file to use.§
  if [[ ${args:0:11} == '--makefile=' ]]
  then
    makefile=${args:11}
  fi

done

`drush dl drupal-$version.x`
`drush site-install $profile --account-name=$user --account-pass=$pass --db-url=mysql://$mysql_user:$mysql_pass@$mysql_host/$mysql_db`
`drush make $makefile`


Example usage:

~/path/to/script --profile=minimal --user=adminuser --makefile=meh.make