CLAIMS
There are several types of acceptable claims. Each has it's own set of rules.
Movie/Show Claim: You can claim an entire tv show or movie, for example: Fringe or The Matrix. If you do this, your icons must include at least two characters from said show/movie. If it is a show, you should icon at least two different episodes.
Character Claim: If you claim a specific character, for example River Tam, all your icons must be of that character unless the theme states otherwise. You may show other characters in the icons as well, but the main focus should obviously be your claimed character.
Episode Claim: If you claim a particular episode, for example Battlestar Galactica episode "33", all your icons must be from the episode. You should show at least two different characters.
Season Claim: If you claim a specific season of a TV show, such as season 2 of The Sarah Connor Chronicles, all your icons must be from that season and/or the promotional artwork for that season. You must icon at least two characters and use scenes from at least two episodes.
Pairing Claim: You can claim a specific pairing, such as Sawyer/Kate. If you do, all your icons should have that relationship as it's focus. Pairing claims do not have to be romantic, you could choose to claim best friends or mortal enemies. As long as all the icons focus on that relationship, you're golden. You do not necessarily have to have both characters in every icon as long as you can somehow make it clear that it's about the relationship.
Story Arc Claim: If you choose to claim a particular story arc, for instance The Pylea Arc in Angel, all your icons should be from episodes in that story arc. You should have icons of at least two different characters and at least two different episodes within the arc.
Actor Claim: You can claim a specific actor. If you do, you should icon more than one of their scifi related roles. If they have only been in one scifi role, than you can use shots of them out of character. The point is to differentiate this claim from claiming a specific character.
Group Claim: You can claim a specific group of characters, such as the Women of Dollhouse, the Spies of Chuck or the Military of BSG. All your icons must contain at least one character from that group. Your icons should feature at least three different characters from the group overall.
As acacia_123 pointed out, there are some scifi characters with several versions of themselves running around. Claiming them will come down to a case by case basis, depending on what has been claimed beforehand. For instance, if you wanted to claim John Connor and nobody else had claim him you could claim John Connor (all) and icon every version of John Connor to appear. However, if someone had already claimed John Connor (T4 version) you would have to pick one of the other versions of John to claim.
This also comes into play in shows that have characters with multiple bodies/personalities running around, like BSG. If someone claimed Boomer, someone else could claim Athena, but if someone claimed Number Eight, nobody else could claim any of the Number Eight versions.
If you have any questions or an idea for another claim category, feel free to share.
Movie/Show Claim: You can claim an entire tv show or movie, for example: Fringe or The Matrix. If you do this, your icons must include at least two characters from said show/movie. If it is a show, you should icon at least two different episodes.
Character Claim: If you claim a specific character, for example River Tam, all your icons must be of that character unless the theme states otherwise. You may show other characters in the icons as well, but the main focus should obviously be your claimed character.
Episode Claim: If you claim a particular episode, for example Battlestar Galactica episode "33", all your icons must be from the episode. You should show at least two different characters.
Season Claim: If you claim a specific season of a TV show, such as season 2 of The Sarah Connor Chronicles, all your icons must be from that season and/or the promotional artwork for that season. You must icon at least two characters and use scenes from at least two episodes.
Pairing Claim: You can claim a specific pairing, such as Sawyer/Kate. If you do, all your icons should have that relationship as it's focus. Pairing claims do not have to be romantic, you could choose to claim best friends or mortal enemies. As long as all the icons focus on that relationship, you're golden. You do not necessarily have to have both characters in every icon as long as you can somehow make it clear that it's about the relationship.
Story Arc Claim: If you choose to claim a particular story arc, for instance The Pylea Arc in Angel, all your icons should be from episodes in that story arc. You should have icons of at least two different characters and at least two different episodes within the arc.
Actor Claim: You can claim a specific actor. If you do, you should icon more than one of their scifi related roles. If they have only been in one scifi role, than you can use shots of them out of character. The point is to differentiate this claim from claiming a specific character.
Group Claim: You can claim a specific group of characters, such as the Women of Dollhouse, the Spies of Chuck or the Military of BSG. All your icons must contain at least one character from that group. Your icons should feature at least three different characters from the group overall.
As acacia_123 pointed out, there are some scifi characters with several versions of themselves running around. Claiming them will come down to a case by case basis, depending on what has been claimed beforehand. For instance, if you wanted to claim John Connor and nobody else had claim him you could claim John Connor (all) and icon every version of John Connor to appear. However, if someone had already claimed John Connor (T4 version) you would have to pick one of the other versions of John to claim.
This also comes into play in shows that have characters with multiple bodies/personalities running around, like BSG. If someone claimed Boomer, someone else could claim Athena, but if someone claimed Number Eight, nobody else could claim any of the Number Eight versions.
If you have any questions or an idea for another claim category, feel free to share.