Hi,
There are many things to consider, but don’t forget to build your own client base.
I see way too much beginners freelancers (in my experience) starting with a fancy portfolio site, social media but zero marketing ideas
Building a website or having social media is one thing, but how will you reach people besides social media? In this case, architects & people in construction you mentioned…? What kind of services are you going to offer?
It’s nice to have broad skills, but what makes you stand out so people will hire you?
You ask or this is a good idea, well I think you should decide that for yourself 
Maybe this link could be useful for you: Branding Brief Template - #3 by pastorshanewest