A Guide to Classic Who references (and other references) in New Who episodes.
Warning: May contain Spoilers for
"The Girl in the Fireplace"
- 01-01 "Rose" (Suggested viewing - introduction of characters.)
- Children in Need - "Born Again" or Christmas Special 2005 - "The Christmas Invasion" (Suggested viewing - reintroduction of character.)
- 02-03 - "School Reunion" (Suggested viewing - addition to cast.)
[1ST] - The first appearance of things in Doctor Who series.
[NEW] - Things that first appeared previously in the new series.
[NEW] - Things that first appeared previously in the new series.
[OLD] - Things that first appeared in the classic series (or the film.) Episode List.
- [OLD] The 18th Century France - Previously visited by the First Doctor during the French Revolution in "The Reign of Terror." He called this his favourite period in history. Long term Second Doctor companion Jamie McCrimmon came from 18th Century Scotland. ("The Highlanders).
- [1ST] 1758 or 1759AD - See below.
- [1ST] Jeanne-Antoinette Poisson, Madam de Pompadour - Historical figure, first appearance in Doctor Who.
- [OLD] 51st Century - Magnus Greel (from the Fourth Doctor story "The Talons of Weng Chiang") and Jack Harkness (Ninth Doctor stories "The Empty Child" to "The Parting of the Ways") both come from the 51st Century. The Time Agency was based in the century. Jack was one, Greel feared being tracked by them. The Ninth Doctor noted that the era (and therefore Jack) was more sexually liberal than Rose's time. The 51st Century is 3000 years from the year 2007 (from the previous episode) not from the 18th Century of the precredits scene, suggesting that the "3000 Year Later" refers to the events of "School Reunion." The Fourth Doctor story "The Invisible Enemy" is set in 5000 AD, the last year of the 50th Century, however, this is the first time the 51st Century has appeared on screen. (Unless you count the Tardisode.)
- [NEW] First go - Mickey joined the Rose and the Doctor to travel in the TARDIS in "School Reunion," if this is his first go then there were no adventures in between.
- [1ST] Dagma Cluster - First mention of this star cluster, two and a half galaxies away from the Mutter's Spiral (the Milky Way.) [M45 Pleiades star cluster pictured].
- [1ST] 1727 - First mention of this year, nothing significant historically or in Doctor Who happened in August that we have been shown.
- [OLD] The TARDIS Translates - The fact that the Doctor's companions can understand (most) other Earth, alien and historical languages was only brought up once previously. The Doctor's companion, Sarah Jane Smith, asked about it in the Fourth Doctor story, "The Masque of the Mandragora." The Doctor stated that it was a gift of the Timelords to allow companions to understand other languages. In this story it was also revealed that the gift stopped the companions from noticing that they shouldn't know the language. This fact allowed the Doctor to deduce that she had been hypnotised. Rose asked about it in "The End of The World," but is wasn't explained how she noticed. In "The Christmas Invasion" the Doctor being unconscious meant that the TARDIS was unable to translate for the humans in the story, but was able to once he awake (although some words were untranslatable.)
- [OLD] Clockwork Men - The Second Doctor encountered Clockwork Soldiers outside of the universe in a void called the Land of Fiction ("The Mind Robber). These Clockwork men appear to be unrelated.
- [OLD] Two hearts - The fact that the Doctor had two hearts was first noted in Spearhead in Space, the Third Doctor's first story. Previously it was implied that the First and Second Doctor only had one heart. Since then it is usually implied that Timelords always have two hearts (with early references being retroactively regarded as goofs) although some non-televised sources claim that Timelords have only a single heart in their first body (or the number changes). Other non-televised sources state that the First Doctor and his granddaughter Susan actually had two hearts. In the new series, the Ninth Doctor's two hearts were shown in "Dalek."
- [1ST] The Yew Tree Ball - An actual masked ball held in the Hall of Mirrors at Versailles on the night of 25–26 February 1745 at which King Louis XV met Jeanne-Antoinette Poisson.
- [NEW] The Missing Crew - Parts of the crew appear in this episode, whole people appear briefly in the Tardisode for this episode.
- [OLD] Time Lord Telepathy - Various incarnations of the Doctor had telepathic conferences in the Third Doctor story, "The Three Doctors," the Fifth Doctor story, "the Five Doctors," and possibly the Sixth Doctor story, "The Two Doctors."
- [OLD] Sarah Jane Smith - Sarah Jane Smith was the companion of the Third & Fourth Doctor, and appeared in the previous episode "School Reunion."
- [OLD] Cleopatra - The Fourth Doctor claimed to have learnt his swordsmanship from the captain of Cleopatra's bodyguard. ("The Masque of Mandragora,")
- [NEW] Lonely - Continuing this season's theme of the Doctor being lonely.
- [OLD] Doctor Who? - The Doctor's Name.
- [OLD] The Daleks - Ever heard of the Daleks? If not: The Daleks.
- [NEW] The Oncoming Storm - First used in "The Parting of the Ways."
- [OLD] Banana - OK, just the fruit, but whatever. The Sixth Doctor found one in his pockets in "The Two Doctors." The Ninth Doctor swapped Captain Jack's sonic blaster for one in "The Doctor Dances" (and episode also by Steven Moffat.)
- [1ST] Multi-grade Anit-Oil - First appearance of this substance.
- [1ST] Five Years before she turns 37 - As Jeanne-Antoinette Poisson was born on the 29th of December 1721, Rose warns her in either 1753 or 1754.
- [1ST] She is complete - Since she's turned 37 is it either the last three days of 1758 or sometime in 1759AD.
- [OLD] Lord of Time - Obviously a reference to him being a Time Lord, the rulers of Gallifrey.
- [1ST] 15th of April 1764 - Is her date of death, with this obvious occurring immediately after.
The 10 Rules to Doctor Who.
(Read the rules here.)
10. The TARDIS is for arriving at the location of the story at the beginning of the episode and leaving at the end. This is because Time Travel is the excuse for the story, not that the story is about. Unless the episode is written by Steve Moffat, then it's definitely about Time Travel.
Lots of Time Travel through "magic doors" only 2 trips with the TARDIS. The Doctor specifically mentions that as they are part of events they can't use the TARDIS to change them. It's actually about time travel and it's by Steve Moffat. 
9. No one can cross their own Time Stream, except when they do.
Jeanne-Antoinette Poisson hers her future self, but doesn't completely cross her own time stream. [.5]
8. There's no situation that can't be briefly defused by a non sequitur.
A story about bananas for example. 
7. The Doctor is both the most serious and most frivolous person in the room - any room - at the same time. And he does that without becoming insane. Mostly.
Did I mention the story about bananas? 
6. The last episode of every series must contain the Master or at least one Dalek. Every time. However briefly.
Not a series final. [NA]
5. The main companion will be a young contemporary British female. Although, to be
fair, almost everyone in the Universe is British and most things happen in contemporary London.
Young contemporary British female companion and her young contemporary male ex. (Set in the 18th and 51st Centuries). 
4. The more emotionless a species, cyborg or robot the more likely they are to be destroyed by emotions. This is true of the Daleks. It is particularly true of the Cybermen.
The Clockwork Robots are probably emotionless, but more confused than destroyed by emotion. [.5]
3. Even if the episode title contains the words "Dalek(s)" or "Cyberman/men" the presence of the Daleks and or Cybermen will at the beginning be treated as a mystery and their revelation a surprise.
Spoiler for very early events. 
2. The nature of the threat will be revealed to the audience before the Doctor. The truth behind the threat will be unknowable by the audience until it is explained by the Doctor.
True to rule, except, in the end the final twist is only known to the audience. [.5]
1. The most dangerous creature in any situation is the last of its kind. This sometimes also applies to aliens other than The Doctor.
Nothing say these are the last of their kind, but the Doctor is and remains dangerous. [.5]