After I have cube cut my flakes and the tobacco is properly dried, I use the 3 step method with a twist. I will fill the bowl to the top and pack it down lightly, then fill it again and pack it a little tighter, fill it again and put some real pressure on it, fill it again with even more pressure. I also make sure to pack it in around the sides at each level. I check the draw after the third and fourth fillings because I have had practice doing this, but for someone new you should check after all all of the levels. I like a really tight pack because I have found my flakes smoke better this way. When I am done it feels like sipping through a straw but there is noticeable resistance. Some times if there is a little tobacco left, I will even load it a 5th time and really stand on it. You have to be careful with a 5th, sometimes I get a little greedy and then I have to start all over again.
Packing a pipe is really not a simple thing, but it is so important to being able to really enjoy a bowl. Once you find what works best with different pipes and different blends, it will become second nature. Patience is important so do not get frustrated. You can always dump it out and start over.