The prolific Sarah Hoyt talks about technology, change, and selling books. She makes a point which we endorse to the fullest extent possible. Of selling books Hoyt says, 'One thing that seems to work is writing a lot.'
The more you write the more you sell. We noticed this with magazine articles. The more we turned in work, the more work publishers wanted turned in. We'd write a piece on Orde Wingate, next thing we'd know a magazine would want a piece on Slim in Burma. Do a lot of work on the Israelis and the magazine would want a piece on 'the other side of the hill' which led to a fun article on the Arab Legion.
We write novels. We hire people to edit them. We have other people proof them. We hire people to design the covers, usually.*
As far as traditional publishing goes, don't know, don't care.
Conventions? Never been to one.
We don't even advertise anymore. Not one dime. The Austrian Painter just got its 14th review, also 5-stars, so we must be doing something right.
*We did To Survive the Earth, War of the Red Sea, and Israel at War.