Goofs

When Dylan arrives at the Pritchett family dinner, and Phil notices that he brought his guitar, Dylan's gig bag switches shoulders between shots.

At 15:14, When Dylan rings the bell to the Dunphy house, he is carrying a hard-shell cello case on his back, not a soft guitar case (as is shown when Phil opens the door)

When Mitchell goes outside to see his Dad in the pool there is a glass of whiskey to his Dads left. When the shot cuts back to his Dad, it has disappeared.

Claire's mother mentions her ex-boyfriend as "Ricky", but in the 2nd season, when her mother visit's again and brings her ex-boyfriend (Matt Dillon) he is referred to as "Robbie".

It is alluded throughout the show though that Claire dated a lot in her teenage rebellious years, so she likely just dated two different people with similar names.

When Haley starts fighting with Luke on the couch at the beginning, you can see the battery pack for her microphone strapped around her waist.