Start by reading the safety section of any reputable <u>instructional</u> reloading manual like the one from Sierra or Speer. Hodgdon makes little recipie books with some safety precautions but the others have instructions and fully explain the propper reloading process. READ THE WHOLE THING. It will tell you what things might indicate excessive pressures.
Next, don't load a single kernell of powder in a case if you don't have a published recipie for it using a very comparable bullet. When you learn more you may want to venture into the area of developing loads from sugested recipies and may even go on to develop loads on your own but for now I would say if you don't read in in a respectable load book then don't trust your vision and/or life to the load.
FYI steel has a tensile strength of about 70,000 PSI. Many rounds generate 40,000 to 50,000 PSI and can climb much higher quickly if you don't follow the rules. This is regardless of the case size. For example: a .22 high velocity rimfire round often develops more pressure than a .44 mag.
The information is available for the reading both here on the internet and in book form. It will be time well spent.
(Did you notice that I didn't give you a quick and easy answer? It is something you should spent some time studying before you start throwing powder.)