Concrete finishing

[Millwright]

Hello,

I'm laying some squares of concrete in my garden. The intention is to finish a smooth surface. The first square is nice and smooth, I think it raining a little helped, as I managed to trowel it nice and smooth.

I've done a few more and I can't seem to get past a few slightly proud swirl marks and some ripples. Now, really the question is of a latent nature, is there a way I can finish off these swirls once the concrete has set? I know the pros on a large area would be using a power float, but what could I use?

Thanks in advance.