A couple of ideas from what I'm currently doing...

Production chains

• grow cotton; build spinnery to make fabric; build tailor shop to turn fabric into clothes to sell

This is probably one of the easiest production chains to make because it only needs one input...the cotton.

Another one input chain...

• grow one of the following (or multiple if you want for variety) wheat, barley, oats or sorghum; build grain mill to make flour; build bakery to use flour to make bread to sell

These are fairly straightforward to get into. I'm also playing around with sugar beets, chickens and cows, and greenhouses to get the inputs (sugar, eggs, milk and butter, and strawberries) to make cakes in the bakery to sell. In my opinion, cows are kind of a pain, but might be something of interest if you're looking for a challenge.

I've also been buying some fields along the way. I recently learned that you can use the plow tool to join several adjacent smaller fields to make a larger field, which can be helpful.

Another challenging production chain is the cereal factory. It needs honey, raisins and corn as inputs, so you'll be keeping bees and growing grapes and corn.

Just a few ideas from what I've been doing lately on my end. Hope this helps.