Brake/Gear adjustments

Hi folks, I did try posting in the technical forum, but it wouldn't let me.
After a long hiatus, got the bike down and took it for a quick spin to check it works ok. The brake/gear changers on my shimano rx100's do not drop down a gear very well. If i push the lever far to one side-nothing, what i have to do is gently move it until i feel it "engage" and then push it all the way to drop a gear.Everything is clean and a squirt or three of wd40 has been used.Any suggestions or website links greatly appreciated.

While i'm here....when pedalling the right arm "clicks". I have checked the pedals and also the crank and rings for movement/tightness, but it seems fine, all I can think is that the BB is knackered even though there is only about 1000 miles use, again any thoughts...

I found this site whilst considering getting an old Cannondale killer v, always wanted one back in the day,after looking through some pages on here i best start saving some pennies!

Thanks for any help.

The best starting point is the Park Tool website.

For a quick summary:
Disconnect the rear mech, set up the end stops (high and low limit screws)
Screw the mech cable adjuster in fully, back it out one turn.
Put the shifters into top, pulling the cable taut and clamp the cable.
Shift down one gear - turn the adjuster a quarter of a turn increments until it shifts cleanly onto the next cog.

Usually a little more finicking with the adjuster on the other gears and you are done.