I planted some potatoes for the first time this year and they came up fine. right now they are about 18-24 inches tall. But the leaves are slightly brownish.
Is this normal, or should they be a deeper green?
Is there some fertilizer that can help them along?
Also I haven't seen any flowers yet.

What was your pre planting preparation for the soil ryan?
Is the browning on the edges of the leaf or thru the middle or in spots etc?
Do you know the Ph of your soil?

It might be normal, but they should have flowered by now and so maybe you have potato bugs or something. Mine are all done flowering and they are starting to droop and die. I used Root Crops Alive by Gardens Alive. Another possibility is soil that is too clay and wet. Potatoes like loose soil.