Oh poor you. I feel for you. It can be very difficult when you get yourself locked into a downward spiral. I think there have been some very good suggestions here re positive reinforcement.
I'm a teacher of 10 years and have worked with difficult students for whome star charts, etc haven't worked in the past. To be honest, they didn't work because they weren't administered properly. Sorry if this sounds critical, it's not meant to.
If I was you, I'd target three behaviours only and make a chart for those eg putting shoes on in morning, putting dishes in sink in evening, reading 2 pages of a reading book to me. The behaviours need to be very specific eg getting ready for school isn't a good target because it's got so many parts to it.
I'd talk about what I expected at various times in the morning/evening so child was aware of what was coming up.
If child doesn't achieve target, I'd just say, unemotionally, 'Oh that's a shame. Still I'm sure you'll do better tomorrow.'
If child does achieve target,praise masssively and talk about his achievement in front of other people.
Sit with child before starting star chart explaining what it's all about. Make sure you put enough preparation into it. Type up the star chart, make it colourful, laminate it if you can. Maybe go to shop and choose stickers with child. Then talk him through it. Put it somewhere noticeable in the house. Be very upbeat about it. Decide in advance what reward he'll get on eg Saturday for eg 10 stickers (don't expect perfection). Try not make the reward non monetary.
Separately from this set up a marble jar. Every time you see him being nice in the house, tell him what you liked and put a marble in a see through jar eg I liked the way you gave your sister that pen. That was good sharing. you are a good sharer.
When the see through jar is full, he gets to choose a special day out with you. he'll be in charge of choosing from a limited option eg day at a special park, day at the zoo, day jumping from trees, etc.
The secret with this is to try to catch him being good. At first this might be hard but once you get into the habit it will be easy. Eg I liked the way you didn't make a fuss when I said we had run out of cereal and you had to have toast for breakfast. That shows that you are a big boy.
Also, when he's being nice and not smirking, I'd talk about the effect of the smirking- not in a victim like way. Eg do you know what a smirk is? (he might say no if he's being a smart arse). This is what a smirk is (demonstrate). When you do that how do you think I feel? Well, I feel.....
I might let the odd smirk go (wanting to pick battles as people have said) but I wouldn't put up with a general attitude of disprespect.
Ok so in summary, here's a possible action plan:
set up three behaviours chart
set up marble jar
talk with him about smirking
focus only on three behaviours and work on catching him being good.
you may then find smirking, horrid attitude decreases. This is usually what happens. Kids like being praised if it's done in a meaningful way.
You do need to invest some time and energy to change this behaviour but it can be done. If you put the hard yards in now, life will become much easier in the long term.
Wishing you lots of strength.
Jacky
once behaviours are established start setting zero tolerance for smirking, etc