You need to start taking notice of the type of foods you are eating and when you are eating them. Make sure your diet is not lop-sided, i.e. eating four hundred grams of protein, fifty grams of carbohydrates, and zero grams of fat. The key to getting a great pump is carbohydrate loading like hell the day before and the day of your workout. This will make sure that your glycogen (energy) stores in your muscles are at a maximum, and also you'll have some glucose on reserve when you begin lifting and burning up glucose (For more information on glucose metabolism, refer to "A Nutrition Lesson" by me).
Now let's be smart about this. You don't need to eat low-grade carbohydrates like pizza (Note to reader: Phano Som does this and does not care). Try eating about eighty grams of carbohydrates per meal in the form of some kind of pasta. I like to eat instant brown rice, which is very nutritious, and one bag is equivalent to about eighty grams of carbohydrates. Pretty much any type of pasta will work. Personally, I don't eat many carbohydrates for my last meal, but that is just personal preference. In my opinion, the most important time to carb load is right after a workout. I crave for carbohydrates after I workout hard because my body absorbs it like a sponge in water. It makes perfect sense, your muscles deplete glycogen stores, therefore they will quickly absorb the first form of glucose you put in your body.
Another little secret that you might want to try is eating a bunch of salt with every meal. True, excessive amounts of salt can cause hypertension, but so can drinking a lot of water, or taking creatine. After finding out the effects of elevated salt intakes, I put salt on everything I eat, EVERYTHING. My workout partner sometimes skips his food and tips the salt shaker over in his mouth (Note to reader: He's crazy!). I think I will stick with putting it on my food for now. The sodium in salt is the key component. Sodium aids in muscular contraction, thus when you workout, your body will have an extra component to help you obtain a higher quality workout.
Try drinking two glasses of 2% milk. 2% milk has very good levels of protein, carbohydrates, and fat. It is also loaded with calcium, which aids in muscular relaxation. I know, it seems kind of absurd to take something that will relax your muscles, but think about it. When you are doing a set your muscles contract, blood is squeezed out, and then your muscles relax and refill with blood. Muscle is like a sponge, ring it out by contraction, and fill it up by relaxation. When your muscles fill with blood, you really feel the results of your set, so it makes perfect sense. Don't drink 2% milk at every meal, rather, drink it about 30 minutes to an hour before your workout.
After almost every set, I like to flex and stretch the working muscle. I don't mean strip down and have a posedown in front of the mirror. Just flex your muscle quietly and then stretch thoroughly. This is very important especially when you first begin with your workout. Not only will you be able to get a pump just from flexing and stretching, you will also prevent yourself from getting injured.
Finally, the way you workout may be your downfall. I have never understood why people go to failure on their last set of the last exercise of a workout. If you do that, you've noticed that you get a great pump, and you feel like you've actually done something in the gym, when in reality, that last set has done more for you than your entire workout. What if you did every set like it was your last set? I mean, what if you went to failure on all of your exercises? Don't be scared of the burn, it's what you want. It's supposed to hurt, really bad too. I will say it forever, high intensity for thirty minutes is ten fold better than half-assing it for two hours. Now don't lose your mind and start supersetting every workout. Yes, supersets are good from time to time, but stick to a "normal" workout. You need to rest long enough to catch your breath, figure out where you are, and then hit it again.
In conclusion, eat smart, carb-load every meal, keep the salt shaker nearby, drink 2% milk before you train, flex and stretch, and shut up and lift. Good luck!!