Thank you RobA_Oz
Yes that was a big mistake.
Those where hand held pictures, I have never tried a monopod, wich probably is helpful.
As an advice I will say go out and try even in the streets of your city, practice does the master, and panning is no different.
There are some rules I like to use. Whether the less zoom I use, the lower shutter speed I can use. I mean, I found like there are 3 important parameters for a good panning a part of a good place. I consider the speed of the vehicle (it's easier if you do your photos in a slow corner than in a fast straight line where the bikes or cars are speeding up!), I condiser as well the distance of the vehicle (the closer you have it, the less speed I give to my shots. Let's say you can pan at 1/125 at a certain range between you and the vehicle, but if you close up, I believe you should go up to let's say again as an example, 1/200, and if it is way far away you probably go down to let's say 1/60, it all depends on how far is it from you). And the last one I will say is feeling comfortable with the speed you are shooting at. I mean, some are comfortable at 1/20 and others at 1/500, it is just a matter of you, you know yourself after panning some times, and so do what you find more comfortable with and after having some good shots, you can start going down in the speed. Just to try how well can you do it.
I remember last year for the F1 grand prix in Austria. I started panning at 1/125 wich I feel comfortable normally, and there was quite a good distance between the F1 cars and me so I could use it right, and then I slowed down my shutter speed down to 1/15. Of course, by any 1/15 picture of that day that was good, I had let's say 40 blurried and out of focus! But you know, it's just a matter of trying if you have the chance.
Oh! One more thing that might be helpful, even tho I thought professionals that use it are not so good (wrong), if you can shoot in speed burst shooting (is that right? I just googled that and I am not sure), I mean the mode in wich you take more than 1 photo when shooting at the time if you keep pressing your camera button; this is really helpful because you'll have 4 or 5 similar photos but it might be that 1 or 2 of them would be good
Hope that helps