Short answer: start with a keychain, bookmark or card holder
Good first projects are small, flat and use little leather. A keychain or key fob, a bookmark, a coaster and a card holder all let you practice cutting, stitching and edge work without wasting much hide. A card holder is a classic first stitched project, and many beginners finish one in one to three hours.
Small flat projects
Keychain or key fob
Use one piece of 4 to 6 oz veg-tan with a rivet or Chicago screw. It’s scrap-friendly, and it teaches cutting, edge finishing and setting a rivet or screw. The steps are in how to make a leather keychain.
Bookmark
Use 2 to 4 oz veg-tan. Bookmarks are a good place to practice stamping and simple tooling, as well as cutting and edges.
Coaster
Use 6 to 8 oz veg-tan, about 4 inches (10 cm) across. The whole perimeter is edge, so a coaster is a good way to practice edge work.
Card holder
Use 2 to 4 oz leather, cut into two or three pieces. A credit card measures about 85.6 by 54 mm, so leave room for the stitch margin and a few millimeters of ease. Keep the stitch line 3 to 5 mm in. A card holder usually takes one to three hours, and it uses well under a square foot of leather.
Next step projects
Simple bifold wallet
A bifold wallet is a good step up from a card holder. It adds more layers and more stitching, and a beginner typically needs about four to ten hours to make one.
Belt
A belt is one strap of 8 to 10 oz veg-tan, or a pre-cut belt blank, with a buckle and either Chicago screws or a stitched fold. Common widths are 1.25 in (32 mm) and 1.5 in (38 mm). Belt length is often your waist or pant size plus about 2 inches to the center hole, though conventions vary. A belt is simple in shape, but finishing the edges over that length takes time. Long cuts are where knife slips happen, so use a strap cutter or clamp your ruler. How to cut straight lines in leather covers the method. A belt usually takes two to five hours.
Cuff, cord wrap or pen sleeve
A cuff bracelet is 6 to 8 oz veg-tan with a snap closure. A cord wrap is a small strap with a snap, and it teaches snap setting. A pen sleeve or sunglasses case practices folding and stitching a long seam.
Projects to leave for later
Bags with gussets, watch straps, multi-pocket wallets and holsters ask more of your layering and edge work than a first project should. Notebook covers and dog collars are good intermediate projects, once the basics are steady. For more ideas, see DIY leather projects.
Thin leather isn’t necessarily easier to start with. It stretches, and it’s harder to finish at the edge.
How to pick your first project
Choose something you would actually use, that fits a small piece of leather, and that you can finish in an evening or two. Scraps and remnants are fine for a first build, so you don’t need to buy new hides. For the cost of materials, see how much it costs to start leatherworking. For how long each project takes, see how long it takes to learn leatherworking.
If you’re making a few of the same project, what to do with leather scraps covers how to use offcuts for practice. For a path from first project to larger pieces, see how to learn to make leather goods.