Over the years I've developed a system of working out when friendships will work and when they won't.
First of all; is this a person a genuinely kind person, or at least someone I can see myself being friends with? This is about the most important point and you may discover that the person is not as nice as you first thought. if this happens, don't be afraid of cutting them off, since there is nothing worse that friends who have a negative impact on you.
Second; does the person have similar interests, ideas and opinions as me? The person in question doesn't have to be a perfect copy of you, just someone who you can talk to who will talk with you about your interests. It doesn't matter how nice a person is, if they don't like the same things as you it won't work out. This may also take a few meetings to work out, but a person who is nice to you can still be a good acquaintance to have, so you can still hang out with them if you feel like it.
Third; can I and this person form a bond over time and have enough interactions to form a bond? This may differ from person to person, but I myself have a lot of trouble with long distance relationships. If the person that you want to be friends and you are able to meet fairly often, even if its just to go shopping of just to hang out for half an hour or so, then you could definitely be friends. This is why people who work, study or live near one another often become friends. You need to have meetings like this in order to learn more about them and their interests, and so that they can learn about you. Again, the time between these meetings can be different depending of your ability to handle long distance friendships.
Also, remember that this process can take a long time and that you cant rush it. It's like any relationship, it has to develop and evolve over time. For instance, my best friend and I first met about 5 or 6 years ago in high school, through a mutual acquaintance. He is about 4 years older than me, so we didn't have any classes together, but we hung out during lunch and whole school activities. We also had another friend, who moved 2 years ago and we lost contact with him. We first realised that we both liked the same movies and tv shows and that we had a similar sense of humour. This about when you can consider the two of you friends. After about a year of of meeting at school, community events and other situations that we were both at, he and my other friend asked if they could have a sleepover at my house for the weekend. After that, they came over once every month or two, and we introduced each other to our families and other acquaintances. At this point we were good friends. After about two years of meeting, going to each other's houses and stuff, we had basically reached the point where we were best friends, meaning that we literally invited each other to everything, went to the movies, gave each other relationship advice and generally trusted each other with everything.
Sorry for the super long post, but that was my guide for making friends, based on my life experience. Feel free to ask if you have any questions.