Upgrade yellow ward. Always. No exceptions.
If you play
,
, or anyone else with ward interactions and do not upgrade it you are severely lowering your potential.
In ANY other situation you will also become nearly unkillable with proper warding because the enemy can never gank you.
Warding is the one most important thing in League.
Alternate tip: Always google your lane opponents' champions before the game is done loading immediately once you see what they have. Learn their abilities on the wiki or Champ Select [You champ vs their champ] ASAP. If you are really unsure about how to fight someone or you think they are a "counter", wait for them to make the first move and the mistake and always capitalize on their mistakes. i.e
premature Windwall,
premature spin,
wasted shield, AND ANY TIME AN ENEMY FOLLOWS YOU INTO A SWARM OF YOUR OWN MINIONS. The little guys really hurt.