These are simple logical deduction Problems. For this, it is always useful to take a pen and a paper and write down whatever you have.
For instance, in the specific problem you linked, We know from the given information that,
L likes Yellow color. O likes Shooting and Q likes Dancing. This is the information that is given to us in the problem.
Next step(2), we see some indirect references:
"The Photography guy likes Cream Color. And the Bird-Watching guy likes Pink Color.". Again, this is the information we know and this can be very useful to solve these types of problems.
Next(Step 3), let's look at some other information:
It is said to us that the travelling guy does not like Black,Red and White. From Step 2, we know, he doesn't like Pink and Cream too. So, The Travelling guy can like only Blue or Yellow. But, from Step 1, we know that L likes Yellow and it is given to us that L does not like Travelling. So, The Travelling guy likes Blue! Similarly, we can deduce that the Hunting guy likes Black!
Next Step(4), we go into specifics:
Let's look at O because we know that O likes Shooting. It's said to us that O doesn't like Black or Red. And We know from Step 2 and Step 3 that, O doesn't like Pink, Cream, Yellow or Blue. Thus, O can only like White! Thus, we now know all of O's preferences. Similarly, we deduce that Q can only like Red! Thus, we have everything about Q as well. 2 down for now.
Next Step(5), we look into the clues again:
It's said to us that P and R don't like Cream color. And M is not a Photographer. From Step 2, we know, neither of P, R or M is a photographer. We know, for sure from Step 4 that, Q and O are not photographers. L is not a photographer because he likes Yellow. Thus, Clearly N is the Photographer and likes Cream color. Similarly, we can say that L's hobby is not Photography, Hunting, Shooting, Dancing, Travelling or Bird-Watching. Thus, L likes Surfing. Thus, now, we know everything about L,N,O and Q. 4 down!
Next(Step 6), we again try to deduce about the others:
From the remaining 3, we know P is not Hunting or Bird-Watching. So, he must be the travelling guy who likes Blue! It's given to us that R doesn't like Black. Thus, from Step 3, R doesn't like Hunting. Thus, he must like Bird-Watching and also likes Pink! By elimination, we are left with only M who must like Hunting and Black! There you go! All 7 down!