I wouldn't say I'm an expert on strawberry's by any means, but heres my advice.
I would trim back all the old brown leaves, and if you have any runners that have set roots, you could trim the vine leading to them. These will be the fruit producers in future years. I organic garden, so in my case chemical fertilizers are out, but I do dress around the plants with some enriched compost. The compost I use is locally available, and is called Sea Soil, which is a two year old soil made up of forest floor humus mixed with fish by-products, (heads, tails, guts). It has approx. 2% nitrogen, and is a little on the acidy side, which strawberry's like.
If I was to use a chemical fertilizer, I would use the Miracle Grow Fruit and Vegetable product. It seems the best of the bunch for the veggie garden. You should retain some mulch around the plants, straw is good. This will help keep the soil moist, and help keep down the weeds too. It also prevents the berrys from sitting on the dirt, as they ripen, and rotting.
Hope you get a good crop!
