Hello again ahmedkl!
I'm glad to see how well you're progressing, your F2L seems to be coming along nicely too! The cross can be a bit tricky, I find it to be one of the areas where I improve slowest. However, it is very important! With Fridrich, our main goal in inspection time is to try and see how to solve the
entire cross, as well as to spot our first F2L pair. When you can pull that off, you've given yourself a strong start to what will likely be a great solve.
There are a couple of ways to practice solving the cross. Firstly, you'll want to make sure the moves you are using to solve the cross are fairly optimal. Once again, badmephisto comes to the rescue with an amazing tutorial
here.
Once you are fairly familiar with the kind of moves you should be using, many people recommend solving the cross blindfolded (or just with your eyes closed). So take as much time as you need to plan out your cross, shut your eyes, and try to solve the entire cross. The point of this is to be able to solve the cross with out looking at it. Later, you will be able to use this skill to follow other pieces which will shortly be the start of your F2L.
A big debate with the cross is cross on top Vs cross on bottom. In theory, cross on bottom will give you better look ahead into your F2L (as you can see those pieces) and I have to say that I do buy in to this. However, there are some very good cross on top solvers. I'd be remiss if I didn't also mention those who feel that the cross should at times be made on the left. This can really depend on the case you have, and it's just something you'll have to develop a feel for over time. Again, a good cross on bottom video can be found
here. I will warn you now: If you are currently solving cross on top and want to switch to cross on bottom, you will notice a huge increase in your times at first. I found this one of the most difficult things to break into, but now it's second nature, and I'm glad I did it.
Perhaps the most important thing while solving the cross is to know your colour scheme perfectly. For cross on white, for example, you should know that red is opposite orange and blue is opposite green, as well as how red and green are positioned with respect to each other and orange and blue, etc.
And then, of course, there is practice. Practice practice practice, and don't give up!
Good luck! =)