Have a look around in your area and see if there's a gardening/horticultural club you can join. Your local library (assuming it's still open!!) can be a great source of information. This site is fab for asking specific questions, and people are full of great ideas when you have a problem to fix.
The best advice I have to offer is check to see if you've any typical weeds, I'm sure you know what nettles, bindweed and brambles look like. If you've any of those, the weedkiller approach is the way to go before they get established. Keep on top those things that are known weeds (things you really don't want in your garden, I don't think many people want a garden full of nettles, dandelions and bindweed).
If there are just the two of you, then I advocate the wait and see approach. HOWEVER, if you've got small children, you need to check and see what's poisonous. I would never have lupins in my garden, I've got two small children that don't listen when I tell them you only put food in your mouth (the eldest has JUST turned 4, and is still a swine for eating things he shouldn't).
Sounds like you're lucky having a big garden with some veg beds there. If there's nothing growing in the veg garden, plant some 'green manure' such as clover or phacelia, these are plants that supress weeds and trap nutrients from the soil. You grow them over winter, and dig them in come spring, to give your veg seedlings a good start. buy or borrow a 'gardening year' book, or treat yourself to a GW subscription, they're good to read as general knowledge, and if you're really stumped, the collected knowledge on here is amazing!