Wanting to buy an ENS that someone else owns. 
I see it on OpenSea, but it's not explicitly listed for sale. 

Do I just make an offer for it?
Is there a better way?

Building /streme. Wanna be the very best. ゼニゼニ

Elevating onchain creators 

@nodefoundation @brightmoments 
@ampsfun

Bidding can alert the owner to demand, which might encourage them to renew just to extract a higher price. If it's not urgent, I would keep an eye on it until the grace period expires and then participate in the auction once it hits a price you find fair.

Thanks for picking this up.

The one I was looking at on OpenSea expires in October. 

Another Is currently in the grace period until late July (have this on my calendar but not sure what to do after that).

Yes best way is to make a bid. Also type in the ens in Twitter (see if they have an acc and dm them), also check their primary ENS name to see if they have records set, like email etc

You can make an offer but best bet is to use the openseas page or address etc to try and locate them and reach out to them