Choose evenly sized potatoes. When it comes to roasting, size is of utmost importance. Opting for potatoes that are all roughly the same size means that they will cook evenly. Furthermore...
Cut them into even wedges! It doesn't matter if your potatoes started out the same size if you hack them into uneven pieces. Depending on the size of your spuds, you can opt to cut each one into 4-8 wedges.
Don't cut the potatoes until you're ready to roast. Potatoes, like apples or avocados, have a tendency to oxidize and turn brown when exposed to air. They are not something you can really prep ahead of time, but with a recipe this simple, you really don't need to.
Don't use jarred lemon juice. Just trust me - freshly squeezed makes all the difference.
Give the lemons a firm roll on the countertop before cutting to get the most juice from them.