Did you try using keyframes.
In modify: depending on the type or nature of the Effect you may set the effect intensity, the strength, etc to zero. The may not work with all, but I guess with many.

Quote Does anyone know how to fade an effect in or out? i can only get it to be abrupt in and out?

I literally just had this same question. My only solution I found was to produce just that section from the timeline and then re-add it back to the project and fade the produced part as normal. I knew there had to be a better way but sometimes I am just too pressed for time to research so I just push through what I know will work.