I would like to make a list of all these thing which optimize the framretate and all the others,which slow it down,so let's get started :
Actor LOD (Level of detail) this can be found in the enviroment setup entity,shortly it changes a high poly actor with a low poly actor when you get in a defined distance from it.You'll have to make a low-poly version of the actor you want this to be applied to,you can read about that in the documentation.
FarClipping I assume that everyone knows what far clipping is,it can be found in the Enviroment setup too and it's a pretty good choice if you want to optimize an indoor level.
Marking unseen brush faces as sky - I do this in all of my levels and it really helps (or at least I think it helps

Models - making figures,which are made from several brushes models.I think that really speeds the game up.
Making small brushes empty - I'm not pretty sure about this one,but I thik it should be optimizing the game since collision is not used.Also for lights on the floor (which my game has) or something like that it's very uncool when the player collides with them,he stops moving and you have to avoid them.
Detailed- marking small brushes detailed.Once again,I don't know how does this help,but I posted a topic like this before and I think Jay told me this,as he is a moderator of the forum I beleve him

Full Vis - When you click the build button in the level editor,chech the Full Vis box.It will take some time for the editor to compile the level,but it's REALLY working.
Let everyone who knows some more tips and stuff for optimization or for framerate killers,it would be nice if you post it here!
I don't have much time now,but I'll post some more tips soon! Oh yeah,If I'm wrong about something,correct me immediately,I don't wat people to screw up something in their games because of me.
