My official disclaimer............I wouldn't do anything to my dirt until I gathered a soil sample from a minimum of 10-12 different areas of the garden. Take the sample to your extension office and have it lab tested for vegetables, list what you grow. You will then get a "complete" picture of what you need to do for amendments, if any. Until you "know" what you have, how to "fix" anything is purely a guess and may do more harm than good. The soil test will guide you on your amendments and application rates. I have mine tested in early spring and again in the fall.
You also want to know whether your soil is classified as sandy, silty or clay. That will make a difference in how you amend. For example in adjusting pH, more material is needed to change the pH level of a clay soil than for a sandy soil because clays are more resistant to pH changes than sand. Never overlook the possibility that some plants are not able to get to or use the nitrogen, calcium, phosphorus, sulfur, potassium, iron, manganese and so on that is already in your dirt without a pH adjustment.
For right now, if you think it's lacking in Nitrogen, Phosphorus, and Potassium (N,P,K), then in absence of a test, I'd suggest a "balanced" fertilizer. Something like 10-10-10 or no more than triple 13. Your application rate would be fairly close on these two, might reduce a hair on the 13.
I use higher P when starting the garden, balanced as a side dressing for corn and a higher K for side dressing potatoes. I feed at on set and again for corn when they reach about 10-12 inches (they feed heavy) and when they tassel. At blossom for spuds (when they're initiating their tubers). I also feed the tomatoes when they set, but light on N. Balanced for Cukes when they start to climb and set.
In the fall, get another test, because chemical fertilizers can cause some soil acidity. The test will let you know if you need add lime or sulphur, and should be indicated on your test.
In addition to compost, I always add a substantial amount maple tree leafs and any other soft wood leafs I scrounge. I also plant a good green manure cover crop. I use hairy vetch, crimson clover and winter wheat. But YMMV.
My .0125 after taxes.