>>717334010Walk around and explore the map while trying to remember which locations you've visited and which you have not, if you see something that you want to check out on the map mark it so you see where it is while playing.
There is no reason to rush Margot at the start.
You have a lot of things to explore before doing Stormveil Castle. However, I suggest beating Margot once you have a +3 weapon so you can access a smith who can upgrade your weapons further.
I recommend focussing on dodging in his second phase until he starts using his weaker moves again.