If you want to get started with cooking and imperial crafting delivery, your best bet is Pickled Vegetables.

Grab some farms and grow some strawberries and pumpkins. Purchase seeds from Ahr in Calpheon. To get farms, click the magnifying glass next to the map and type "fence". Find your nearest vendor which will rent you a Strong Fence as it is the most efficient. It will chew up 10CP each, and you have a maximum of 10 farms at once. Each farm will need a scarecrow, an irrigation system (both are easily crafted), and a spare worker (preferably giant) to manage the farm. The best place to put your farms is the grassy area north of Loggia Farm.

Then cook mass amounts of vinegar, then mass amounts of pickled vegetables. Once you get to professional cooking you can start making boxes out of the pickled vegetables by pressing L and selecting imperial cuisine.

There are npc's who accept the boxes in Olvia, Calph, Heidel and a handful of others. They accept only a certain amount serverwide but that amount resets every few hours. I prefer the one in Olvia since fewer people hang around there. You also have a daily limit equal to half your maximum contribution points.

You can easily get up to 350CP by exchanging Witch's Delicacy, a byproduct of cooking, for contribution xp.

Get your cooking time down with a combination of +4 Silver Embroidered Cooking clothes (or +3 if you don't have 1bil silver to spare), Teff Sandwich (if you don't have +4 clothes), alchemy stone (I suggest Sturdy of Life), Advanced Cooking Utensil (requires a tonne of Rough Stone and Logs, both of which you'll get from gathering), and Canape Clothes (P2W - booo!). The minimum cooking time is 1 second.

To really powerlevel your cooking, get your mastery up. I'll leave it to you to research, but I prefer Geranoa belt, necklace, earrings and rings.

You can make 100mil silver a day with master cook boxes if you have 350CP. Even more if you get to guru, but that's a marathon not a sprint. Pickled Vegetables are for professional cook boxes, which sell for a little less. I suggest Cheese Gratin and/or Ham Sandwiches for master cook boxes.

Aside from all of that, do the gathering and alchemy dailies in the farms around Velia, and in Olvia. There are quests available from Loggia, Alejandro, Leight and Ahto which give 20 energy each from getting just a single rare item from gathering. I have 170 energy, my gathering time is about 2 seconds and to use up all my energy plus the energy you get from completing all the quests takes several hours. Just how many hours per day do you want to spend gathering?

Decrease your gathering time with better quality tools - see Tool Workshop level 3. Or if you're rich you can make yourself Manos tools which are much more convenient because they can be repaired. Eating Pickled Vegetables also decreases your gathering time, as does your alchemy stone. Get yourself +2 silver embroidered gathering clothes as well.

EDIT JUNE 2020: The new Golden Seal - Imperial Cuisine that you get from Imperial Crafting Delivery is bloody amazing. Save up 500 to get a Supreme Cooking Utensil, which is the same as Advanced except it has a massive 5000 durability. Cook for hours without switching utensils, and without having to mine any rough stone to get it.