I do 3 exercises per muscle group.. Work 3 groups per day. 1st set is a set i can do without much strain.. Then i add about 20kg.. Do that set with 10 reps.. Add another 15-20kg do a set of 6 reps and then add another 5kg and do 2 reps. If i feel like it i then do a burn set.. This method works for me, i started gym a week ago again and started off on 20kg bicep curl machine and now am on a comfy 45kg-50kg as my comfy starting set.

Free weight isnt as much but thats because the machines are very well balanced. Its always good to do free weights and i find they give better results.