Starting with fishing and cooking is a great idea since food is essential for early survival. You’ll also want to focus on quests that unlock important areas, items, and transportation, as they give great early-game progress without needing the GE. Training skills like thieving for easy money and agility for faster travel are also very helpful.
On top of that, getting early combat gear from monster drops or quests can make things much smoother. Farming and Herblore are worth starting early too, since supplies take time to build up. Above all, set small goals and build gradually — Ironman is all about long-term progression.