Is there some place where I can learn about what you guys are talking about? I feel so intimidated reading this thread. WTF is a rally bot?
Also, how should I reclass characters? All I've done so far is reclass my Avatar because it got to level 20 (upgraded it to grandmaster). When is it a good time to use second seals? Most of my characters are now approaching level ~17.
http://serenesforest.net/fe13/skills.html
Characters can learn Rally skills from certain classes and boost the stats for your units within a 3-tile radius until the start of your next turn. Rally bots have several Rally skills equipped like Spectrum (+4 to all), Rally Heart (+2 to all, + 1 move) and others (luck, str, magic). Using Rally ends that character's actions for that turn, so they can't attack. As far as I know, you can't have the same Rally stack (so 2 characters with Rally Spectrum will only end up in 1 working), but they do stack with other Rally types.
If you're skill hunting, use Second Seals at level 10. Long story short, the exp decay will be less harsh on you later on. General rule is: Second Seals at level 10, Master Seals at level 20.
http://serenesforest.net/fe13/index.html
^ Everything you need to know should be there.