Trouble adapting some things from Softimage to Maya 2018

[Anonymous]

Hi! I'm an Animation Student, and I have 3D classes. In my bachelor degree, I was taught Softimage over a year. But now in Master's degree I'm learning Maya, but in less than a 1/3 of the time (A bit less than half of a semester). That being told, our teacher besides doing his best to teach us everything in so little time, he can't cover all of our questions.

My biggest trouble with Maya (besides the fact that I sometimes I try to use Softimage shortcuts by mistake, but I'm getting better at not doing it) is that I can't reproduce some very useful things I could easily do in Softimage, because I can't discover how to do them.
Example:
- In softimage, everytime an edge is duplicated, it gets highlithed, thicker than the other edges. Maya doesnt do this. I know that there is a duplicated edge somewhere (I notice it when I use smooth) but I don't now which one. 

- In Softimage, if i selected an edge or face and then duplicate it, I could easily extrude the edge or face. Even tho I discovered how to extrude faces (but it is not as good as softimage) I can't duplicate edges as it did in Softimage (it would create new edges around the edge I selected, very good for making hard edges or grooves.

For now these are the things I miss the most. I'm a fast modeler, but since I changed to Maya I'm twice as slower if not more.

Maybe my question is a bit confusing because english isn't my first language, but if you can help me I would be very grateful!
I made a drawing of what I want to do to help.

[Fovvl · Accepted solution]

You can work in smoothed version and select that edge in the mode and then go back or deleted the edge in the  smooth mode. Also I think that clean up may show or solve this kind of things.

[Anonymous]

Thank you! I will try that!