a good practice...

a text editor...

if you have a home lab, or gns3, or even using rack rentals this is a good technique to get used to...

before touching the machine or machines that you want to configure, pre-configure your work using a text editor, then scrape it in and see where it succeeds or fails...

in a production environment, you will almost never have the opportunity to simply configure the machine hot, you will be tasked with pre-configuring your changes, presenting the change to the group, and then be approved (or not) for plugging in your values during the change window...

think of the time you will save, especially with rack rentals, if you pre-configure your work before logging into the system... it will force you to have a plan before beginning the tasks you want to perform... you will ultimately save money if you are on the clock...

this will get your head into the machine before your fingers get into the machine... it will also reinforce what you know, and will glaringly point out what you don't know...

this will also serve to weed out sloppiness, and decrease your time at the console, which for lab testing, is vital...

it is often fun to be sloppy on your home lab, using the ? mark often, mistakenly thinking your making progress when in reality you are only reinforcing bad habits...

try pre-configuring a l3/l2 switch block on paper? first after erasing start and reloading, from the very begiunning... don't just copy a known config, type all the commands  without the help of any reference before touching the machine and see where you screw up...

this technique will make you faster and more accurate in your head while reinforcing commands, especially lengthy commands...

consider every pre-config you write to be a test, and time yourself during the process...