The emergency fund should generally be larger — 6-9 months of expenses rather than the standard 3-6, since there's no second income to fall back on if the primary earner faces a job loss or health issue. Life and disability insurance for the earning spouse becomes non-negotiable rather than optional, since the family's entire financial stability depends on that one income continuing.
It's also worth considering income protection more broadly — building some diversification in skills or a side income stream, even a modest one, purely as a hedge against the concentration risk of depending entirely on one job or one employer.
On the investment side, the same principles apply as any household, but with less room for aggressive risk-taking on money earmarked for near-term needs, since there's no second income to absorb a bad year. Goal-based planning, mapping specific investments to specific timelines, becomes especially valuable here to avoid over-committing to any single risky bet.