When Jodie is making her shake she adds some ingredients, blends them, then adds some more, but does not blend them again. However, when she pours the shake, there are no large lumps in it.
Luthor's letter from Metropolis has a state abbreviation of Ka (printed with one capital, one lowercase). No US state has that abbreviation. Since Metropolis is in Kansas, as Smallville is, the state should be abbreviated KS.
Towards the beginning of "Craving", Whitney tells Lana that he's been invited for a football try-out on Saturday and further adds that it's the day of her birthday. Later Jodi, Chloe, and Clark are eating lunch in the school's lunch room. Jodi mentions that she's nervous about the party that night. If they are in the lunchroom then the party is scheduled on a Friday, not Saturday as was previously mentioned.
In one establishing shot of "Smallville High School", the building's actual name, "Vancouver Technical School", is still visible on its front (in later episodes this is edited out).
When Clark and Chloe begin their investigation on the Deer, when Clark pulls the blinds, you can see the shadow of the crew equipment on the left side of the blinds.
It is not reasonably explained why Clark was able save the day after Jodi Melville ignited the gas pipe of the greenhouse. Normally, a prolonged exposure to meteor rocks results in Clark's incapacitation.
When weakened by the meteor rocks, Clark was also able to take a shovel to the face from Jodi and fall into glass without receiving any cuts, bruises or bleeding at all. It is ironic considering that in later seasons, Clark gets wounded and bloodied by less, such as a single punch to the face, even though Clark becomes more powerful and more tolerant to kryptonite as the series progresses.