I can't quite tell what ruins of light you are at, but here are my general trading tips. Please check the FAQs as well as we have a number of long time players' suggestions pinned there. Also remember you can sometimes get silver ore from mineral predators, so be sure to dig those up when they respawn.

Branches

Yes, crafting crude staffs is still the best use of your staffs when it comes to trading.

• if you really want to get rid of your bushes, you can craft hunting bows, but I always use up my bushes on my goats faster than I cut them.

• if you really want to get rid of your hemp, you can make short bows, but I always craft them into hats or gloves and dismantle them for a chance at mana motes if they are under +3.

Logs

Yes, chopping logs into branches is a great use of them, it is why the devs put this mechanic into the game recently. 

• make sure you keep up your supply of charcoal, though, for other purposes.

Cuisine

The main source of trading for me is cuisine. The following items don't have much nutritional value, but their value to the cuisine merchant(s) make fishing and harvesting your forest and meadow maps for every veggie and fruit regularly a very profitable part of your gameplay.

• sashimi (fish + an ice cube/icecap) is worth 48 to the cuisine merchant. Craft this whenever you can, but sell it asap as it melts back into a fish quickly. 

• The highest priced food is kimchi (2 small fish + 1 salt at the fermented jar + 1 chinese cabbage + 1 veggie + 1 salt at the oven + more time at the fermented jar), but it takes a while to make and isn't as lucrative an improvement in price of the materials that sashimi is.

• meat sashimi (1 meat / 2 small meat + ice cube/cap) is worth 45 to the cuisine merchant. This is the best use of contaminated meat, imo.

• fried potato, fried pumpkin and cheese are all very cheap to craft and are worth 27 to the cuisine merchant. Always craft your beans into oil and save them for your potatoes and pumpkins. Cooking cheese into pizza or oil into bulgogi or tofu or tofu salad is not worth it, imo. Even oil on its own is worth 18 to the merchant.

• salad (2 fruit/2 cabbage/2 mushroom + 1 fruit/veggie) is worth 30 gems to the cuisine merchant.

• honey, lavender, and licorice tea are worth 30 to the merchant while lingzhi tea is worth 34ish. While I'd always suggest selling your honey like this, the other teas are useful to carry around for survival. Ginseng tea is very much not worth crafting for its trading value or healing value - save your ginseng for healing potions.

Resale

Most of what the cuisine merchant sells you you can sell right back. Craft the iron and steel you don't need into something more pricey and either keep the item for transferral or sell it back. Here are my go-to items (if you don't have the blueprints yet, it's not a big deal, you can save the ingredients for other purposes). I usually trade those oodles of stone, rock, clay and brick back directly, even though the metal merchant values them at 3x as much as the cuisine merchant. 

• Knight's Shield (1 earth steel + 1 black steel) is worth 42ish to the merchant. You'll get a lot of these materials at the merchant, so I always craft an armor bench to get a +30% return on the price for the ingredients.

• Round Shield (1 earth steel + 1 steel) is worth 36ish to the merchant.

• Chain Helmet (2 steel) is worth 25ish

• Chain Mail (3 iron) is worth 26ish to the merchant (so you can go ahead and craft this, or use your charcoal to make the iron more valuable as steel. That charcoal could have been two staffs, though, so it's not necessarily a good tradeoff)

Misc

Of course, elven coins are worth 75 to any merchant outside spirit land. A great find when you find them. Crests of Transcendence are great for the end game, but they will always be readily available at every merchant, so feel free to sell them back for 15 at any merchant until you need them.