Step 0 (Legit AF). Select destination or throw a dart on the world map? I prefer SkyScanner! They also have an option to search for flights anywhere in the world during a specific month. It's a boon for indecisive people like me hehe!
Step 1. Look for cheap flights/train tickets. Again, Skyscanner ftw. (Duh! Stating the obvious, Pragya)
Step 2. Contemplate how broke you really are, think about going somewhere cheaper.
Step 3. Cry. (Very important)
Step 4. Browse for discounts, check up all the various possible combinations achievable within a limited budget for the initially planned destination - Mamma didn't raise a quitter.