An around complete meal would be to add compost. Work a little into the planting area and then top dress with a light layer and cover it with a nice organic mulch. For mountain laurel, be sure to plant just a little bit high (you want the last 1/2 inch of the root ball to be above the soil line; the mulch should cover it all up). It needs good drainage and planting it a bit high helps.

What was your soil pH level?

In a quick web search I did not find the specific numbers you wanted but many sites said to basically follow the same regime used for rhododendrons. I help look after some land with a few mountain laurels and they have survived for years with no human help except for pulling out invasive vines.

the 2 areas we're looking at have the following numbers
#1
pH 5.3, Phosphorus 22, Potassium 26, Magnesium 33, Calcium 29
#2
pH 5.4, Phosphorus 13, Potassium 9, Magnesium 26, Calcium 9

That seems to be an ok pH number for mountain laurel. Adding compost (you can often buy it bagged - like mushroom compost or composted cow manure) will help provide good slow release nutrition.

Compost is a wonderful soil amendment and conditioner, but often does not contain the nutrients and trace elements needed. Holly Tone is a highly organic complete fertilizer and is specially formulated for acid soil plants like mountain laurel. By all means use compost and mulch, but the addition of a complete fertilizer in early spring can be a big help.