How to fix headset and bottom bracket?

hey
I have a njs headset, which I can't tighten fully as steering then becomes sluggish. How do I tell if the bearings need replaced, or if the cups have been damaged so then the whole set needs replaced, any tricks to learn?
Also, in cycling today and yesterday I noticed that my left crank arm was clicking on the down pedal stroke. I pulled over and grabbed the crank arm pulling it towards me and away from me, I then noticed that the whole body of the cranks and chainring felt loose. Has anyone ideas about this and more importantly how to fix it. I have recently had the BB tightened by a mechanic as he thought it was loose then, it should not be loose so soon again.
Any ideas ??

What do you mean by 'tighten fully'!? A headset top race should be tightened only enough to remove play in the headset and still allow smooth and easy rotation of the fork, it should never be done up what one might consider to be 'tight'...
Re. the BB issue, what kind of BB is it?

Hussy has a nag, so most likely to be a Hatta like this:

http://www.parktool.com/repair/readhowto.asp?id=127

http://www.parktool.com/repair/bikemap.asp

Assumption: you have a loose-bearing BB.

Sounds like your bottom bracket non-drive-side cup has come a bit loose.

You need some specialist tools to fix this, but they're worth having - if you have a loose-bearing BB, you should be taking it apart and cleaning it every so often anyway. You'll need crank pullers, a lockring spanner and a pin spanner. Park make nice ones that look a bit like oversized sugar tongs. Take it all apart, give it a good clean and re-pack with plenty of grease. Putting the lock-ring / non-drive side cup back on isn't difficult but there's a certain knack to it. You can feel when it's right.

^+1, sounds like the BB is loose again, and as per my previous post you are over-tightening the headset - both BB & HS are adjustable ball bearing races, both require the same approach when adjusting i.e. the adjustable part (lower nut on HS, adjustable cup on BB, the bit with the holes drilled in it) should be tightened only enough to remove play, then the locknut/ring tightened. Doing this may slightly change the adjustment, can take a few goes to get it perfect. If either HS or BB feel 'stiff' after adjusting, they're too tight. The BB lockring needs to be VERY tight and is best achieved with proper tool.

people thanks for all your replies on this, sorry to late response from me, been away and no computer with me. I get what your saying about the BB, I do think it is loose and needs to be taken out and greased-up oh and cleaned before hand. I do understand that the trick is not to overtighten but to get the right torque feel and tightness. It is a hatta BB. the headset is a delux njs, a bike mechanic tightened it for me as best he could so that I would have free movement but he did say that he could not tighten to recommended torque. when you stomp the front wheel to the ground there is a feeling of looseness and also much rattle, not too bad but generally feels loose. I was wondering if I replaced the bearing casette would that work, or how to recognise if the cups where damaged in the headset, this I would not be able to tell. The whole bike rattles, I think it is my wheels, I had them built by a bike mechanic too in Belfast, but he is a lazy drunken worker and hates fixed gear. My spokes make a flat sound. I know I should just get the bike to a shop, or the brilliant Harvey at city bike shop.
Do people lend each other tools in thios forum, is that accepted. I aint got the money to buy any, seriously. But I would get someone a beer and two.