Walls and Ceilings - seams showing through paint

i am a recent first time homebuyer. i am fixing up the bathroom and want the walls to look nice. i've mudded a few spots that were bad. but i noticed the seams are showing in certain areas of the wall. at least that's what i think they are. should i slap some mud on it and sand later?? or try sanding now?? just looking for the best way to level out my walls and make them look good...
thanks..

What you say are seams showing are ridges in the wall or discolored areas in the wall where seams in the sheetrock are likely?

If they are ridges of joint compound, just sand them with some 120 - 150 grit paper and prime then paint. If they are discolored areas, just prime and paint over them.

If this is joint tape that is pulling loose, it will have to be removed and replaced prior to priming and painting.

If I have not addressed the issue because I don't understand it, post back.

A good way to check to see if you have a flat wall is to take a twelve inch knife, put the blade on the wall vertically and see if there are any gaps. You can also do this with any straight edge. If there is a gap where you say there is a seam showing, fill with mud.

i'll check it today when i go over there to do some work. i'll post back later... i don't think the tape is coming up. just looks like horizontal ridges in my walls.. i'll check to se if it's level. maybe they just didn't do a good job painting... i am going to prime everything first anyway...