Never start baron if they're all missing and also stronger than you.
If you lost the majority of your towers and they have map control, start warding your own jungle and objectives.
If you see you have a clear disadvantage against another champion, play safe, meaning you can't get in range of him, only go in to last hit, and if that's not possible, play passive until you get a gank but make sure to ask for one too..cause some junglers "forget" to gank.
Play a champion until you know who he does good against and who does good against him.
If a player dies twice in a row..go gank that lane...immediately, and preferebly twice..to give your lane a chance to comeback.
If you have a squishy team, make sure to pick/have at least 1 tank, and preferibly with cc.
Everyone must ward. Top and mid included.
If both teams are of equal strength, ward their blue/red for possible ambushes you may do.
Don't try new builds/roles in ranked unless you tried it before on normals and it worked. (not trying once, but several times)
Can't think of anymore at the moment.