You absolutely can sell from within your list build and don't let anyone say you can't. Although the main thing sure is to build your list... the wait to convert
Learn from my (past) mistakes so you get a better result. Time to evolve your promo/connection game or suffer the consequences. Let me blunt (I know you expect that much from me) and share that I get 40-60 emails a day from other marketers pushing their things... and some of it catches my eye and some makes me go "whaaat were they thinking?!"