I would advise a mix of split training (keeping main body parts to seperate days) and CV.
Try and alternate upper body/lower body/CV days.
e.g, my regime at the moment (and for a while now)
Mon- 10min run, Chest/Triceps
Tues- 10/20min run, Legs
Wed - 10min run, Back/Biceps
Thurs- CV/Abs/Core
Fri - 10min run, Shoulders
Sat- Rest day, few Beers (you still need a life!)
Sun- Rest day, (bit of a cheat with the eating, chocolate etc...you wont stick it long term if your regime makes you miserable)
Technique must be good, if its not then drop the weight to until it is. Forget about `gym pride` and ignore what others are lifting, stick to your limits and make susatainable injury free progress.
Eating wise:
Its actually fairly simple but requires discipline and some fore thought into you next meal as `fast food` rarely means `good food`
And if you are training a lot you will have a big appetite.
You will need:
Lots of fruit
Lots of veg
Lots of lean white/red meat/fish
Avoid too much starchy stuff such as white rice/pasta/bread, spuds etc, and stick to brown/wholemeal rice/pasta/bread or cous-cous for a change.
Lots of water
For lean mass growth you will need around 30g Protein every 2-3Hrs, so I would highly recommend Protein powders to supplement the protein intake from wholefoods.
IMO the training is the easy bit, keeping the diet right and the steady protein intake is the hard bit!
Im not an expert but Ive talked to some very knowledgeable people and done it long enough to know what works.
Good luck and stay off the jabs, you dont need them.
Hope this is useful.
Cheers
Paul