Dig in lots of organic matter, compost, soil improver, very well rotted manure, spent mushroom compost, composted bark. Anything that is going to add to the health of the soil.

if it once grew, it can be composted, ie: newspapers where once trees, old woollen jumpers were once growing on sheep that kind of thing. If your not too bothered about organic growing spent composts are excellent but be mindful they will contain chemicals from the original growers. Have a scout around for a stables who always need to off-load manure, this will need to be stacked to mature before useing alternatively dig it in at the end of your growing season so by next Spring it will be ready for your plants etc.

I'd be careful of newspaper, the inks are not good for the compost, personally I prefer to put any paper to recycling, as for woollens yes, if they are 'wool' most people do not wear wool though. Our old woolies have other uses. Horse manure needs to be rotted for at least a year, better two before using and is full of antibiotic residue.... not for the veggie bed in my view. Guest you are going to get various answers to your question and, unless you join GoY, can't answer ot question us! I think it simply depends on your views!