1. Know yourself – Know your limitations. Getting bigger means constantly pushing the envelope. Add 10lbs. more; force the last couple of reps out, pushing yourself. But, BUT … Do not try to bench 200lbs when you could barely do 170lbs last workout. Do not add weights for sake of adding weights. Go for extra rep, take the strength increase gradually. Remember you are in this for the long haul.
2. Know where you are – The gym is dangerous place. The weights and machinery can hurt you badly and in worse case scenario, do the unthinkable. Be careful where you step and where you put you weights. Great, you just pumped 8 reps with 100lbs dumbbells on the incline press. DO NOT drop it to the floor with a roar of contract. Ease it down to your thighs and carefully swing it to the floor. If you had a spotter, the spotter carefully takes one dumbbell and you ease the other down. Know where you are. And in concert with Tip # 1, if you are working out alone at home, be smart. The last you thing you need is to get stuck doing a heavy bench press.
3. Stretch. Before working out, while you are working out, and after you finish working out. Nuff said.
4. Warm-up. Two types of warm up. First, the general warm-up before working out. Any whole body calisthenics for about 10 to 15 minutes. Do jumping jacks, run in place – pumping those arms, the old squat and lunge (add a pushup while you are at it), or anything else you can think of. Key is whole body, gets everything moving. Nothing too hard, just get a light sweat or glow going. Second, the specific warm-up. Every exercise starts with a warm up set of 15 to 20 reps.
5. Wear a sweat suit. Not the ones cut from delt to delt, so as to "accentuate" your massive traps and cut high on the sleeve to show off the arms. Wear a real sweat suit, whether at home or the gym. Wearing a sweat suit keeps your body warm. A warm body is less pronounced to muscle pulls and strains. Not one of the vinyl sauna sweats but a cotton sweat suit let it breath.
6. Work out sequentially. That is, for example, chest – shoulders – triceps. Not so much for the old "keeps the blood in same area" argument. That seems a bit goofy anyways. Bench-press works all three mentioned, but how is the blood in your triceps the same area as your chest. Same for lat pull downs – back and biceps same are no. Now stay with me on this. While back ago, I read an article that said that if you wanted big arms, then focus on just arms for one day. So, I did. Terrible. Arms hurt almost one day and felt I dropped each muscle fiber strand in my arms. Why? First exercise was barbell curl. Went like this – 1st set bar (45lbs) for 20 reps. 2nd set was 85lbs for 15 reps. 3rd set was 115lbs for 8 reps. Last set was 125lbs for max rep, 6 to 8. The strain on the wrist, elbows, and shoulders were incredible. Now, let us look at it sequential. Back workout consists of stiff legged deadlifts, bentover (Dorian Yates Style) barbell pulls (rows), and lat pull downs (can be any variety). At the end of that workout, arms are pumped, no need to push heavy barbell curls. Few sets of dumbbell curls to isolate some bicep work and that is that. Follow the logic? Despite the "25 or 39 inch massive" arms that some of these guys have, the bicep is not a big muscle, relatively speaking, and does not need to be "punished" by itself.
7. Know yourself, yes – Listen to your body. If you are sick, take a break. Long time ago, I read somewhere that if you are sick from the neck up (ie cold) workout. If you are sick from neck down (ie flu) do not work out. Either way, rest. I read once that Nasser El Sonbaty claimed that he could not afford to have on bad workout, because in a given year, he works every body part, say 40 to 50 times (do not remember the exact number). That mean for him a bad workout cost 2.5% of his productivity. WELL … For guys like you and me, this is for the long haul. We want to do this for a life time of benefits. Miss a few workouts if you are sick.
8. Rest. You need it. There is no need for guys like us to work out more than 4 times, or so, a week. We have a job, a life, and family – a bunch of priorities. Taking to do too much, too soon, is a recipe for hurting yourself.
9. Full range of motion. Slow to moderate speed. There can be no better way to rip out tendons and ligaments – pull a muscle, than to throw weight with short range of motion and a weird body English to finish the rep. Use weight that allows you to finish the sets using full and complete range of motion.
10. Always keep a slight bend in your knees. Whatever you are doing curls, press downs, deadlifts – whatever exercise requires you to stand, do it with a slight bend in your knees. Locking your knee puts your lower back in a weak position. Keeping a slight bend helps keep your whole body tight and strong.
There you go, my top ten for working out safely. Hope it helps.