How do I cross-sell in a way that actually helps the customer?

You cross-sell naturally, expanding accounts by meeting needs the customer actually values. That is the mature form of the skill, where growth and service become the same act. Accounts grow because you are useful, not because you pushed. Protect that reputation; it is the engine. The subtle risk is that a target or a good quarter tempts you to reach for a sale the customer does not truly need, and one such move can cost the trust that made all the others easy. Your edge is that customers believe you. Never spend that belief for a single deal. Keep a simple test before each expansion: would I recommend this if my pay did not depend on it. Sell only what passes. The accounts that trust your no will say yes for years.