Whats the best method to lose fat and gain muscle?

Im 6.2 tall. A year ago my life style was really bad. I had always been lean & thin and never had a weight problem until a year ago, I got fat - upto 18.6 stone. Basically not enough exercise, heavy drinking & poor diet. Over the last 6/8 months I have lost most of the weight, I managed by restricting diet dramatically-cutting out all sugar, stopping the boozing (to a certain degree), Trying to avoid all carbs and just eatting protein where possible. Started weight training & generally being more active.
 
 
I want to build up - my arms and legs have gone thin & still have a bit of belly fat.
 
I dont want to get over weight again, so worried about eatting too much. At the same time want to build up, so worried about not eatting enough.
 
My arms are much stronger & leaner now, but also thinner!
 
Any advise?

Get back on the carbs for a start.
 
Research a basic diet plan and STICK to it.
 
Train 3 times per week using only free weights.
 
Doing this for a few weeks should see you lose fat and gain muscle. After that point you can see where you are and consider adding cardio and working on lagging body parts more.
 
 

Well done on kick starting the loss, sounds like you have made good progress on your own so far. I would post your current diet in the 'Diet & Nutrition' section of the website and let people critique and provide good advice.
 
I would also follow a good solid workout plan with heavy compound lifts 3x week (deadlift, bench press, squat), some good examples here -
www.muscletalk.co.uk/Need-a-routine-Read-this-m1326.aspx