The gear is your friend!
Congratulations on your new job flying the 737-800, getting through training and out on the line. Now the real work (and fun) begins.
Three things stand out in your post. First is “it is my first jet aircraft”; this pilot is new to jets and may have limited, or virtually no experience, flying above FL180. Secondly “I’m new 737-800 pilot with less than 11 hours on type”; he/she is cutting their teeth on a complex high performance next generation platform. And finally is the location “Egypt”, so this pilot is either a very fortunate expatriate or a low time national, I suspect the latter.
I am not sure what the flight deck culture is like where you are flying but I would encourage you to speak up and ask the Captains you are flying with for advice. They should be eager to tell you what they have learned. Listen to what they say and watch how they fly, then copy the Captains you would like to be like in a few years. By all means follow the training department’s and the SOP’s guidance. Ask other pilots who are already there what works for them (both Captains and First Officers).
On the NG (737-800) at 30 miles from your destination, and closer, the landing gear is your friend while descending. Drop the gear early to increase the drag will help you get down if you need the help. The jet is so clean that the first several degrees of flaps really don’t to all that much-get the gear down early it can make a big difference for you.
As others have stated, have some parameters set in your mind. What altitude do you need to be at 60, 30, 15 NM from the runway? Make sure you hit those altitudes 60, 30 & 15 NM out and it will make the whole descent much easier.
Are you familiar with the 3 to 1 descent profile? Do you know how to modify the 3 to 1 descent profile for ground speed variations? Are you comfortable with whatever level of training you were given on the FMS to understand what the vertical path is and how it differs from vertical speed?
If you don’t know what a 3 to 1 descent profile is PM me and we will talk about it. My own method is no better than somebody else’s method but it works well for me.