STEP 1: Release comics again.
STEP 2: One artist per story arc.
STEP 3: Introduce some new stuff, which has happened, but now make other books use it. In the 60's, most of their discovies were important to other books, and therefore important to the universe. Why are we waiting until Griever shows up in FF again? There is an entire cosmic line of books! Find some weird thing on Earth and have it show up in Avengers! The reason they were so prominent in the 60's was because as Stan and Jack's biggest and best-selling book, the line orbited around it (really helped that the line was smaller and they were involved in most of it, but we saw this happen in a modern context with Bendis' Avengers). That stopped when they left, and if you want to recreate that you need to do the reverse, where you manually coordinate the line to orbit around FF. This requires a lot of work, but the key thing is that this has to be an active Marvel editorial goal, and with how disparate the line has become under Cebulski we don't really see this happening with any book except Hickman's X-Men for other X-Books. But I don't think profit should be a factor in putting out books that stand on their own but are more than just in the same setting as others, but a line where most of the books are building towards a single narrative for their own corner for a few years.
And you know, I typed all of that before I remembered that the FF is headlining Empyre which does most of what I just said, so maybe we should just focus on Step 1.