If you are using a spinning reel, you'll need a swivel. The way the line comes off the reel will cause the line to twist up into knots if you don't.
If you are using a baitcaster, you can tie directly to the line but most people will use a shock leader (stronger line) tied to the line before tying on a lure.
If you are using soft plastic baits or topwater lures, use a loop knot. If you are tying on a hook, use a palomar knot. They are both pretty easy.
This is a good website that shows you how to tie knots:
http://www.animatedknots.comAs far as weights are concerned, I've noticed far fewer bites with a weight attached to the line directly in front of the spinner. I don't think it deters the fish as much as it really ruins the action of the spinner or lure you're using.
If you want to get deep down fast or increase your casting distance, you can add a weight with a short snood tied onto a 3-way swivel onto your mainline before your lure. Obviously, the snood should have less breaking strain than the mainline in case you get snagged.
This website might give you some ideas:
http://www.geocities.com/tony2kuk/rigs.htmlHope this helps. Tight Lines!