I use pine bark as a mulch and i fertilize with an acid loving plant fertilizer. This is my first year growing blueberries and it seems to work decently so far.

Knowing your soil acidity would go a long way in helping you decide what to do. Blueberries prefer a pH in the 4.5-5.5 range. If you are above that range elemental sulfur is most often used to increase acidity. A prill form is mush easier to work with and won't blow away as you apply it.

You'll hear lots of advise on fertilizer. Applying it (and sulfur) before the mulch will get it that much closer to the plant root zone and that is more important for phosphorus which tends to move very slowly through the soil. Larger growers would most offten use ammonium sulfate for blueberries and depending on the size of your bushes a quarter cup to half cup per plant is usually adequate after the second year. If you use a garden center product like Hollytone (4-6-4) you could (and should) use 5 times those levels safely.

For mulch type I prefer to visit a local sawmill and use their older rotted sawdust. Ask if they may have black walnut sawdust and avoid it. Any other wood sawdust is suitable as are any of the composted mulches at garden centers.The more important point is to get 4-8 inches over the ground extending a foot beyond the outermost branch tips. The mulch should be reapplied every year to keep roots from being water stressed. The mulch layer also deters grubs which feed on grass roots as well as your blueberry plant roots.

Don't wait until the soil is dried out to apply mulch. Now or very early spring are better times to get it on before the other soils are fit to plow.