This photo-tutorial is of "Double Pineapple Doily." You can find the free pattern here on Ravelry.
I won't be including the actual written pattern, but any notes that I think might be helpful, so be sure to have the actual pattern pulled up as well as you work it; the link is provided above. This pattern usually takes me about 400 yards of size 10 thread, no matter what hook size I use. My preferred hook size for all thread crochet I do is 1.50mm. The finished size when using that hook and thread is usually between 18-20 inches in diameter.
ROUND 0 -- You can find a video tutorial here how to do a magic circle.
ROUND 1 -- Tighten your hanging end thread as you go.
ROUND 2 -- To avoid having to weave in this beginning thread-end, work it underneath the stitches in this round. To work a DTR (double treble crochet), see this video.
ROUND 3 -- You can see a video tutorial on how to work a dc3tog here. From here on out, these dc3tog will be called "cluster" stitches.
ROUND 9 -- The 9 TR form the beginning of your first round of pineapples. From here on out, 2DC + CH3 + 2DC will be called a "shell" stitch.
ROUND 10 -- If you want your pineapples to look raised like they do in my green version, then do all your TCs in this round into the back of the stitch post.
ROUND 16 -- For the next few rounds, you will see I've edited the pictures because I wrote the wrong thing down. It is fixed now.
ROUND 18 -- The lonely SC down at the bottom of this picture is the final stitch in this round of pineapples.
ROUND 21 -- TC and TR are the same thing; sorry for the confusion.
ROUND 25 -- TC and TR are the same thing; sorry for the confusion. If you want your pineapples to look raised like they do in my green version, then do all your TCs in this round into the back of the stitch post.
ROUND 36 -- For this round, you will need to complete what I have starred (*) in three places for each part of the final round. There wasn't enough space to write it out each time, so I simplified it a little by giving it an asterisk instead. Watch this video if you don't know how to do a CH 4 picot stitch.
Cut thread, fasten, weave in all ends, and block your finished doily. When I block, I pin it down to a blocking mat, steam with an iron (never let the iron actually touch it), and then spray with a can of heavy starch.