For Harry's supposed 'nemesis', Draco doesn't actually have a huge part to play in The Chamber of Secrets. His main role here is insulting Harry's friends for their poverty or blood-status, being a terrible Seeker, and providing a usefully suspicious figure for Harry to assume is the heir of Slytherin. Despite the fact that he largely exists just to be a sneering bully, he still manages to make a few solid choices throughout the second installment of the franchise.
Some of these choices are only good for him, or his house - which makes a certain degree of sense, and is also an important consideration. Just because a decision isn't positive for Harry, that doesn't mean it is necessarily a bad choice that someone else made! Most of these, though, have a surprisingly positive impact on the overall plot of the franchise.
Buying His Way Onto The Quidditch Team
While this is held up as a bad decision - after all, Quidditch teams are supposed to be comprised of the students with the most skill at the game, not the most money - this was actually a fairly solid choice for Draco. Even though he is not a particularly good player, his decision to get all the team the best racing brooms available give them a serious advantage on the pitch, and a much better chance at winning the House Cup.
This may have been an underhanded move, but Draco is a Slytherin - and within that house, this would probably have been seen as a great move, and one that would gain him popularity and status, making it a solid choice for the ing Harry Potter character.
Conjuring A Snake In Dueling Club
It's not entirely clear how Draco knew the spell that allowed him to conjure a snake to attack Harry at the short-lived Dueling Club (many suspect Snape whispered it to him), but it was actually a good move, on his part. In the short term, this was helpful to him in making people suspect Harry of being the heir of Slytherin - but in the long term, this was instrumental in letting Hermione figure it out.
Harry didn't tell anyone that he could speak to snakes until this happened - and probably wouldn't have, either. And had Harry not told Hermione that he could speak to snakes, she would never have figured out why he could hear the Basilisk but no one else could. Turns out, Draco's seemingly bullying move was a huge help!
Telling 'Crabbe' and 'Goyle' About The History of the Chamber...
When Harry and Ron took Polyjuice Potion and tried to get information from Draco about the Chamber of Secrets, they were surprised to find out that he was definitely not the heir - but thankfully, he still decided to repeat to his 'friends' everything he knew. It would have been easy for Draco to refuse to keep repeating himself, but instead, he happily spilled everything he knew in the Slytherin Common Room!
This decision not only gave Ron and Harry the information that they needed about Draco himself, but helped them learn more about the Chamber of Secrets, and what happened the last time that it was opened. This also became instrumental in figuring out what was going on.
... And The Location Of His Father's Stash
The other decision that Draco made during the polyjuice conversation that turned out to be a great one for Ron and Harry was to reveal the details of his father's stash of illegal artifacts. Ron, of course, immediately told his father, who was able to regain some standing at the Ministry and save face after the car incident.
Of course, this is a decision that was actually a pretty terrible one for Draco himself - after all, Draco's father was dealt a real blow when the raid turned up so many Dark Objects in Malfoy Manor. However, his boasting about his house of Dark Objects was a great choice as far as Ron and the Weasleys were concerned!
Following His Father's Advice
In this installment, Lucius Malfoy tells his son to 'keep his head down' and simply stand back as the Chamber was opened - and one of Draco's best decisions was to follow that advice. While he was clearly wishing that he could do more, he spent most of the year playing Quidditch, studying, and being his usual bullying self - which was a surprisingly good choice.
Draco often goes wrong by trying to impress his father, or by trying to take on his father's beliefs, but a decision here to just focus on being a kid at school was a great one. If he'd only continued doing this, rather than trying to become a Death Eater and show off, proving himself to his father and Voldemort, he would have been a much, much happier kid.
