I'm wondering if anyone knows what effects/ settings I can use to make video look like it's a flashback or a dream? I use adobe premier any help would be great

Why don't you have text flashing at the bottom of the screen that says, "FLASHBACK." That'll work just fine. Or you could do a different color adjustment to give the flashback a different look.

Alas, you probably just want to do a cliché flashback look, with a white border and a B+W or very de-saturated video. (and I'm just as guilty of doing this) Put a white color slug (or solid or whatever premiere calls it) on v1. On v2 put the flashback sequence. To the video, apply an oval matte with heavy feathering. Then apply the de-saturate color filter. Also cliché is the white color dip transition to get in and out of the flashback.

That'll get you started. Then, you can take it from there. Best luck.

i try to do this sort of thing with heavy color correction.

if the current scene is very blue, with deep shadows, make the flashback golden late afternoon, or whatever moods fit your scenes. that's sort of cliché as well... but - what flashbacks arn't?

You could try solarizing it or maybe tinting it a certain way. Anything to make it seem strange. Maybe some kind of weird focusing technique. The ideas are limitless!

it sounds like you're aiming for cliche...do the following:

lower your color levels.
Solarize definitley
Black and white completely?
Make a blue matte with a cloudy outside border and key it in.
Focus on the transition to the flashback...you know...(does the thing they do in waynes world).
In the cheapest courier font you have just have "flashback" flashing in the bottom. That's VERY tasteful in the movie industry.