I'm a beginner drummer, been playing for few months, but mostly playing beats of some songs that I like. However when I tried to make something of my own(I had a guitar player playing some random melody) I failed. Is there any pattern, or something that could help me with making own beats and transitions?
I don't play drums but I had a similar experience when I was learning electric guitar. I'm a bit confused about what you imply when you say 'failed' but I'm assuming you mean you just couldn't come up with original, engaging ideas.
The truth is, there is no real originality when it comes to music. We can be pretty certain the most good drum lines have been used but it's the way you use them that makes it sound new and cool.
The best thing to do is just learn as many other drum lines as you can. Learn your favourite song, learn a genre that you aren't familiar with, learn the simplest, ever drum beat for all it matters but the best thing you can do is grow your field of reference.
Once you've done that, all you have to do is mess around with these ideas, creating similar but varied alternatives to them. Mix up ideas, and add/remove elements. That is what I have done with guitar and it hasn't failed me yet.
Good luck with learning!
One way to make sure you are ready to come up with different beats on the spot is to practice a lot of different patterns. There are a finite number of combinations of snare, hat, and kick, so practicing a lot of these help when you find you are repeating yourself too much. A good book for this is A Funky Primer for the Rock Drummer by Charles Dowd. This book runs down a whole bunch of possible ride/hat, kick, snare patterns.