For me, one of the most fun things about the B5 CCG is seeing how different cards can work together in potential game strategies.
One caution, droping an agenda into play as an endgame move to let you win when you have about 15 (or even less) influence - especially if you haven't played many conflicts - is often frowned on. This is because it can make the game more like group solitaire rather than an interactive multi-player game. Multi-player, conflict-driven play is generally the more enjoyable, and is the strategy more likely to get the other players to play with you again.
[This strategy suggested by Chris Hayes on the b5ccg mailing list.]
On the first turn, declare your conflict.
Pick a player to target (whoever in your play group wins the most...).
Then use Affirm Alliance to bring out Talia.
Use Talia to support your conflict (basically a guaranteed win for you).
The conflict can remove a vital card from your opponent's hand - seriously interfering with their game strategy. Since some, or all, of their crucial cards will usually be too expensive to play on the first turn, they won't be able to get them out before you get at their hand.
You have to hold on to the aftermath and conflict until you have enough cards to be able to win by the required 10 power (unless some evil player has bumped your unrest above 2, in which case you're probably going to have a notably harder time doing this).
Be sure to include lots of characters of your race that have good diplomacy. Also various diplomacy boosting events.
You may want to substitute an "Aide" character of your race in place of your assistant to get a little more diplomacy from the start (unless you're Centauri since the Centauri Aide isn't any better than the assistant).
The biggest weakness with this strategy is that you're putting 2 cards in your starting hand that you can't use for possibly quite a while. However, if it pays off, your hand will grow quite rapidly, hopefully making it that much easier for you to build your power and hinder the other players. (That is, until someone plays a "Reverse Advances" on you - which they can because RA targets you and not your ambassador).
I played this strategy successfully with a Minbari deck (about 180 cards - I like big decks!). My starting hand: Delenn (6 dip), Minbari Aide (3 dip), Consolidated Position and Diplomatic Advantage. I managed to pull a "Popular Support" event around the 7th turn (I think) which gave me 3 extra diplomacy for Delenn allowing me to successfully play Consolidated Position and Diplomatic Advantage.
I then lucked out by getting "The Great Machine" - a difficult conflict which I actually won because I had played a fleet before anyone else did and managed to also play one of my 6 diplomacy characters. So, I had the most strength for both the military and diplomacy conflicts of "The Great Machine" resulting in a 3 influence boost! I got my Homeworld after that. Played "Affirmation of Power" for a 2 influence boost. Then a Trade Pact for 2 influence, followed by Trade Windfall, Carpe Diem, Trade Windfall again and a second Trade Windfall from my now very sizable hand (thanks to Diplomatic Advantage) put me to the 20 influence mark - winning the game.
Combine the Agenda "Defense in Depth" (get an influence for every location you bring into play) and the Neutral Character "Catherine Sakai" (rotate and use 5 influence to pull a location from your deck) in your starting hand. With these, you can quickly build influence while putting locations into play (don't use this until you've built up your initial 10 influence).
You can't have more than one character, not including the ambassador, in your starting hand, so you'll probably want to have extra ambassador's assitant cards in your deck to increase your chance of getting one sooner.
The Minbari can't take much advantage from this strategy (they have the fewest locations to use). The Humans can get the most from it - 4 locations (5, if you use "Sleeping Z'ha'dum"), which could mean they get up to 15 influence fairly quickly (providing somebody doesn't target Sakai right away...). I've effectivly done this in actual gameplay - it makes it a lot easier to make further progress.
You may want to promote Sakai to the inner circle to protect against, or reduce the impact of, the "Extreme Sanction", "Attacking Pawns", "Hate Crime", "Kidnapping", "Na'Ka'Leen Feeder", and "Temptations" conflicts.
This is centered around the Agenda "Support of the Mighty" which gives you an extra Power for each ready character you have with an ability of 6 or more. It also reduces the cost of characters with an ability of 6 or more by 2 influence.
Include characters from other races who have abilities of 6 or more. These are quite expensive (usually too expensive), but there are cards which will reduce the cost.
If you focus on one race (the Narn and Minbari are probably the best for this), be sure to get a "Disaffected..." card for that race (such as "Disaffected Minbari"). If you get that card into your inner circle, you can bring out any character of that race (that's not already in play, or allows multiple) for their listed cost, instead of the normal double cost for playing a card from a different race.
One 'extra' with this strategy is that you might be able to reduce the benefits of another player playing the "Rally the People" and "Consolidated Postion" Diplomacy Conflicts (which are restricted to the player's race).
Build influence and abilities based on destiny marks.
Needless to say, any card that gives destiny marks is useful to this strategy.
Include "Meditation" in your starting hand to help build your hand more quickly. Play it as your first action.
This website is cardware - if you find it useful, you are encouraged to send me a non-common booster card(s) from the game. (email Grant Neufeld for current address)