First of all Welcome to the Lugerforum... I see this is your first post.
to diagnose your issue long distance without actually holding the pistol you will have to answer some questions. Lets see how well you can follow blind written instructions...
Have you disassembled the pistol at all? If not, there are plenty of visual guides available to do so on the internet. There are even some good Youtube demonstrations. Just make sure the chamber is UNLOADED before you begin disassembly.
The following suggestions are for smoothing the trigger pull... NOT reducing the weight of the trigger pull. That process is much more complicated.
Once you know how to separate the upper receiver from the lower... then do so. Then we can start the diagnosis.
Part I:
The trigger linkage parts to fire the gun are contained in both the upper assembly (sear and striker (firing pin)) and in the lower (trigger) and the two halves are coupled by the sideplate (contains the trigger lever) to accomplish the firing cycle. So with the upper and lower assemblies separated, pull the trigger as many times as you like and determine if there is any roughness or difficulty of movement. If there is, determine where the issue is and resolve it by improving parts clearance or polishing carefully... Once you have complete freedom of movement of the trigger we can move on the part II of the diagnosis.
For part II, examine the "L" shaped lever in the sideplate and work the lever up and down with your fingers and determine if there is roughness or binding that needs to be corrected. Once the lever operates smoothly, we can move on to part III of the diagnosis (the upper assembly).
On the left side of the upper assembly you will see the sear (forward), the striker or firing pin (center) and a small flat spring that is the return spring for the sear (rear position). On the very front of the sear is a small spring loaded pin that is pressed by the L-shaped lever in the sideplate to release the firing pin when you pull the trigger. Once the firing pin is released, you can remove the large pin (toggle axle) at the rear of the upper assembly and pull the toggle/breechblock out.
You remove the sear by pressing down on the front end and the rear end will pivot upwards. As the front end of the sear is depressed, the protruding rear end raises the flat spring which can then be removed by pulling it toward the muzzle with either a small flat blade screwdriver, or in my case, a really tough fingernail. Once that spring is removed, check the sear for freedom of movement, and you can remove the sear which sits on a pivot point. Examine all the pieces and again determine if there is any roughness.
All the moving parts can be gently polished with 400 or 600 grit emery paper or cloth and some gun oil. Be careful not to polish any surface which is visible when the gun is assembled.
Once any polishing has been accomplished, clean all parts and reassemble the entire gun and check for smoothness of operation of the trigger components. If some roughness remains, it will likely be on the two surfaces of the L-shaped lever that rub in the groove cut in the upper portion of the trigger, and the spring loaded pin on the front of the sear. You can very carefully polish (not removing any metal) the two surfaces on the trigger lever to smooth out the trigger pull.
Once reassembled after all that work and lubricated with gun oil you should have a noticeably better trigger pull.
Once you have completed this process, please report back on the trigger pull and let us know if you have fixed the problem.
There is an E-book (Luger Mechanical Features) authored by a forum member (Gerard Henrotin) which will teach you all the essentials about the mechanical movements in the Luger pistol. The book is very inexpensive ($7.95) and downloadable. I highly recommend it as a new Luger user as well as the other e-books by the same author on not only the Luger, but many popular firearms. Here is the link for the Luger Mechanical Features e-book:
http://www.hlebooks.com/ebook/eluger1.htm