Anatomy of a Score Track
No game requires a score track, but we all know that pictures speak louder than words...and numbers. Score tracks are basically bar graphs showing each player's victory points in such a way that you can easily see the relative positions. This can play an important part of the decision-making process.
You are behind. Is it the proper time to take a risk in order to catch up? You have a choice of 2 good actions. Is your choice going to be partly based on on which player(s) it adversely affects, and their current victory point status?
While most games with score tracks implement them reasonably well, none get good marks in all my categories. Some games use tracks to manage non-scoring information (eg Through the Ages). Everything below still applies to these.
Zero
In almost every game with victory points, all players start out with 0. If the score track doesn't have a 0 space, then all the scoring markers have to start off the board (eg Aton). This is really lame.
If you don't start at 0, and can never have a score of 0, then this rule does not apply.
Length
Score tracks should typically have 50 (0-49) or 100 (0-99) spaces. Stopping at 65 or 80 creates that awkward situation where you have to do modulus math. For example, you have 75 points and just scored 22. 75 plus 22 is 97. 97 minus 80 is 17, so you place your scoring marker on 17. Maybe...
Did your score track end at 79 and start at 0? If so, then your calculations are correct. If they ended at 80 or (exclusive) started at 1, then you are in trouble.
Wrapping the score track more than once is unacceptable (eg Carcassonne) even if the game includes indicators for such states. Make the track longer than a typical game requires.
Odd-length score tracks are only valid when the highest position (potentially with a little slop to break ties) is a winning condition (eg Around the World in 80 Days).
Size
Each space on the score track should be able to comfortably hold a number of scoring markers that you would reasonably expect to be there. They should not have to be packed together on such a small space that you can't tell which space they are on.
In some games, players cannot co-exist on the score track (eg Torres) so it doesn't matter as much. In some games, the scoring markers are meant to stack (see Markers) to save space (eg Vinci), or for turn order purposes (eg Thebes, In the Year of the Dragon people track).
Pitch
Pitch is the distance from the center of one space on the score track to the center of the next. Pitch should be constant across the entire score track. You may wonder why I don't say that each scoring space should be the same size. That's because size can change while still keeping pitch (see 5's and 10's).
Score tracks are most beneficial in games where players score small numbers of points over many, many turns. Score tracks should provide as many cues as possible to help with this process. One of these is pitch. Every time you score 3 points, you should be moving your scoring marker the same distance. Games that have varying pitch--even if done for other good reasons--take away this cue (eg Taj Mahal).
Obvious
It should be obvious what is and what is not a space on the score track. There should not be "spaces" that are not spaces (eg San Marco). There should not be strange artistic distortions at the start, end, or corners of the score track (eg El Grande).
Art
As I've always said, form should enhance function, not hinder it. Many games go way too far trying to be artsy. This can even infect the score track. Spaces contain dark, rich patterns that only serve to obscure the numbers, if they exist (eg Amyitis).
Numbers
Every space should be numbered. I can't say this enough. Every space should be numbered. Not everyone scores in the same way. Some players just count off their points: 1, 2, 3, 4. Some pick up their scoring marker, look at the current value, add the new points, and replace the marker. If the current space has no number, and the spaces around it are crowded with other scoring markers, then you have to either look farther and count it out, or move things around.
Additionally, the numbers should be highly readable. Fancy and thin (eg Ys) typefaces don't get the job done, nor do colors that don't stand out against the background (eg Caylus).
5's and 10's
Every space that is a multiple of 5 should stand out. Depending on the length of the score track, multiples of 10 should stand out as well.
There are many ways to do this, some of which can be used in combination for good effect: larger text, bolder text, brighter text, different-colored text, different-colored background, different-patterned background, larger space (see Pitch).
In this way, even when a space on the score track has one or more scoring markers on it, you can still easily make scoring adjustments without having to see the numbers.
Straight
Ideally, a score track should be straight. This works fine when the game requires few spaces (eg Liberté), but is impractical for most games. A reasonable compromise is to wrap the score track around the outside of the board. The brain can easily "unwrap" this shape to see the 1-dimensional bar graph.
Winding (eg Alhambra) and wiggly (eg Torres) score tracks are bad. They disrupt the linear flow of the 1-dimensional space, and make it more difficult to tell in which direction to move each scoring marker.
Markers
Scoring markers are manipulated often. The must be easy to pick up, must fit well on the scoring spaces with other scoring markers as the game requires, and preferably should stack. Alhambra-style scoring markers are about the best size and shape I can think of. The worst scoring markers ever conceived are those in Railroad Tycoon.
My Dream Score Track
I'd like to see a score track designed so that the scoring markers do not cover the numeric text. The spaces themselves would just be empty boxes with appropriate colors and patterns. The numbers would appear on tabs that stuck out from each space toward the center of the board. These tabs, of course, would be properly differentiated on the 5's and 10's.