See ClickPop for tips on removing clicks and pops from vinyl recordings.
Manually fixing 'breath sounds' on a vocal recording can take an inordinate amount of time - so if possible avoid them in the first place. A 'pop-shield' between speaker and microphone can help, and can be made cheaply. Here's an easily-made pop filter using a small embroidery hoop and a stocking. It's credited to Jake Ludington.
Repairing Popping Vocals
Here's how to repair popping or percussive vocals. It'll never be as perfect as a good original recording.
1. Make sure the recording's DC offset is zeroed (This in itself will eliminate clicks generated by edits and silences and should be done before you do any editing). Do this by selecting the whole track and choosing the 'Normalise' effect. In the resulting box make sure you've only selected "Remove DC offset".
2. Zoom in on the percussive sound. They're easy to pick up. They look like a big single waveform just before the rest of the sound.
3. Select this waveform and then choose the 'fade in' effect. This will soften the percussive and hopefully solve your problem.