My goal is strength.  I compete in powerlifting and want to perform at a high level.  I'm also interested in competing in Strongman and Olympic lifting.  I've played with different forms of programming from rigid to loose while trying to find out what I like and what works best.  The things I've noticed benefit my goal the most are the following:

High frequency squats and bench at low reps but medium to high intensity.  This might sound like blasphemy to those dogmatic about one body part per session once a week croud but I find that squatting and benching upwards of 6 or more times a week helps me gain strength.  The key in increasing one rep max for the average person is to enforce proper technique.  Technique is dependent on each individual.  The key to making this work is recovery.  Must sleep and eat sufficiently and properly.  

High volume back work.  I like to do chins and pullups almost daily.  I love doing heavy rows and shrugs at all reps ranges.  It seems like I can get away with volume here without as much need for recovery.  A big strong back is far more important than big tits and shoulders for both looks and performance.

Don't neglect micronutrients.  I've noticed when I'm not eating leafy greens and fruits and also not supplementing with minerals like magnesium, potassium, and zinc I lose considerable strength.  Additionally, I experience soreness.

Overtraining is a misnomer.  Despite what all the magazines, blogs, and trainers say - you can lift heavy frequently.  You can have 2 heavy squat days in a row without losing all your muscle mass.  I squatted 13 days in a row before switching to Smolov for both squat and bench and hit massive PR's on all my lifts. This really ties back to my first point.  Train often and train hard.  Being tired and sore is not overtraining.  Having horrible cramps, strains, insomnia simultaneously are symptoms of overtraining.

Compound exercises.  It should go without saying that compound lifts use more muscles allowing you to lift heavier than isolation exercises.  The body is a unit of muscles, tendons, nerves connected together and working together.  Why separate them?  

Don't neglect the arms.  I used to be a squat jockey and thought working arms alone is worthless considering I'd see numerous skinny kids curling to no avail as I did not curl and my arms got larger.  That only goes so far.  Having strong arms helps in heavy pressing and pulling.  It also just looks good.  Just make sure to go heavy and cheat within reason.  So basically stick with the barbell and go heavy.

Exercise selection.  Back squat.  Front squat.  Zercher squat.  Deadlift.  RDL.  Bench press.  Reverse grip bench press.  Close grip bench press.  Chin up.  Pullup.  Power clean.  Olympic clean.  Clean and press.  Clean and jerk.  Snatch.  Barbell row.  DB row.  HEAVY power shrugs.  High pull.  Prowler push.  Sled pull.  Tire flips.  Farmer walk. Yoke walk.  Dips.  HEAVY BB curls.

Full body programming.  Squat + Push + Pull is a tried a true formula for strength and size.  Some lifts are do more than one thing.  For example, olympic lifts are a pulling movement and squatting movement at once.  The jerk adds press to that.  So a day of lots of Olympic clean and split jerks or clean and presses utilizes every part of the aforementioned formula.  Others that follow similar guidelines are Put something overhead, Pull something off the ground, Carry something for length/time.  Push and pull are there along with a weighted carry with follows the lines of prower push and pull and farmer and yoke walks.

Don't baby yourself.  Eat plenty and rest well but don't avoid hard work.  Working a full time job is good.  Being a student is good.  Having physical activities whether they are sports of yardwork are good.  The biggest strongest guys from old times and current times did not baby themselves and nor should anyone who wants to be truly strong.