When Lal pulls Riker over the counter in 10 Forward to kiss him, in the first shot, from Riker's left side, his hands are holding the back of the bar. When the shot cuts to Riker's right side, his hands are holding the front of the bar.
[ca 30:20] Commander Data explains that Lal has exceeded his own programming, and cites her use of verbal contractions as an example. When Data starts his next line, the words "I have" are said quickly, making it sound almost like the contraction "I've." However, both the script and the subtitles state that the line is "I have maintained records on positronic matrix activity".
Data teaches Lal how to blink, but earlier when Data and Wesley are discussing Lal she is already visibly blinking.
Data turns Lal off, but she is still blinking.
In the final scene, when Data resumes his position at Ops, the lower turbolift doors are open, and a dark, open space is visible through the doorway.
When Data, Lal, and Troi enter the holodeck for Lal to choose her gender/form and Data wakes up Troi (who has fallen asleep) you can see staples in the holodeck wall holding up the set.
When Data, Troi and Lal walk around the ship and Lal identifies genders of the crew, a piece of equipment is visible behind an arch.
Androids' rights & freedom of choice were determined in Season 2's 'The Measure Of A Man' which would invalidate even an Admiral's decision to remove Lal from the Enterprise against her wishes. Picard mentions he had a hand in determining Androids' rights but it is not addressed or mentioned again after.
When Data and Lal are choosing Lal's appearance on the holodeck, Troi falls asleep, and then Data wakes her. Troi is sleeping sitting on the floor against the wall, but as this is a holodeck, it would have been simple for Troi to request a chair or a bed to sit/sleep on.
After kissing Commander Riker in Ten Forward, Lal and Data return to their quarters where Lal expresses her first emotion, frustration, at not being able to feel what humans can feel. This is her first emotion and was completely missed by both Data and Lal. This is in contrast to what was meant to be her first emotion, fear, in response to being taken away from her father by the Admiral.