Up your protein intake....some people need 1.5+ grams per bodyweight before they start seeing muscle gain
What?? The body tends to utilize protein more effectively as the g/lbs drop up to a limit of course. There shouldn't be anyone that can't gain at least some muscle on 1g/lbs at the very LEAST. Heck, .5g/lbs bodyweight should be fine of course with adequate sleep, weightlifting routine and otherwise good diet albeit probably not optimally though.