This is so different for everyone I'm sure.
Personally I noticed my face looked a bit puffy. I felt tired and achy it's something that's hard to explain, like a heaviness all over not just in the belly region. And a strange sort of contentment like with my first I was anxious but as I got very close to the due date I wasn't worried anymore IYKWIM.
With my first I didn't get any immediate signs till the day I had Mason. I had a show which then went into contrax then I had the runs. The Dr broke mt waters on the hospital. It was all on after that.
With my 2nd I had a false labour, followed by a very long pre labour 2 days later. I had no show, no runs and no water break till Angus was just about to crown.
My labours were so different with their beginnings, that I guess anything goes for this one!