The ratios of fat to muscle gains is more to do with your diet than training (unless the training is very inadequate, like too little training days and too little volume).
You need to eat enough protein (roughly 1.5g/lb in bodyweight). If protein isn't high enough, you may be eating too much overall calories, which will make you gain too much fat, and hardly any muscle. You could simply "clean up" the diet, and increase protein to make gains.
If strength gains still aren't coming, or stop again, this is the point where you need to increase over-all calories. You will not get much stronger unless you give your body reason to grow. Understand that to be in an anabolic mode, you will gain a little fat along the way (typically 1/3rd of the bodyweight gains can reasonably be expected to be fat)...so don't restrict calories just because your waist has grown a little. Catabolism = fat loss/breaking down, anabolism = building up (including a little fat)
If you are sensitive to carbohydrates you need to curb them (especially simply ones from things like soda). Some people don't see decent lean gains until they've almost eliminated carbohydrates (e.g. the anabolic diet).
Since you asked about training here you go:
You can't go far wrong training muscle groups roughly every 5 days (this is individual, but most seem to respond well to this). Example split:
Push/Pull/Legs, done 4-5x/week
Push day: Chest/Shoulders/Triceps
Pull day: Back/Biceps
Leg day: Thighs/Hamstrings/Calves/Abs
Do 2 exercises/bodypart, roughly 3-4 sets per exercise (last set should be hard/near failure), mostly 6-8 reps/set...except thighs/abs/shoulders which usually respond better to 8+ reps/set.
Make most of your exercises selection multi-joint/compound movements (if in doubt, just pick the exercise that allows the most weight to be moved/exercise that allows the biggest weight increments). E.g. bench pressing vs cable crossovers...or skull crushers vs triceps kickbacks
As you get more advanced, you'll probably benefit from an extra exercise here or there, but don't worry about that just now - concentrate on getting your strength up on the big exercises first.
Don't get distracted by things like periodization/rest periods/reps and sets/changing exercises and routines constantly...If you keep focussed on a basic outline like above you'll be way ahead of 95% of gym goers out there (and do it by your 20th birthday). Knowledge is important, but it's not always a case of training intelligently, it's a case of simply taking action over the long term and putting into practice the basics.
Make strength/bodyweight goals, and don't be obsessed with the strategies of getting there.