The first bit of advice i am going to give about this is that it takes some time. As to how much, that depends a lot on the individual. What you are studying, what your goals are, how intensely you dive into the learning, and how you end up internalizing and understanding the information you come across. ...Long story short everybody is different.
If you are just starting out on a path, it is usually a good idea to start out with meditation. Practice being in the present moment (IE; Here, now.) and developing awareness of your thoughts and energy. By building a sense of stillness, presence and attentiveness you are in effect learning how to listen.
For some people that is all it really takes, considering that people always have guiding spirits around them, helping in the background, nudging things into motion guided by your attentions and desires. Or sometimes giving little nudges or alerts to opportunities or events. By learning to listen to these little signals it helps one to recognize them and be consciously aware of these signals and where they are coming from.
If you want, as you practice meditation you can also make a more formal attempt to let your guide/s know you are wanting to connect with them on a more conscious/direct level. Once you have gotten to your point of relaxation and stillness, or at least as close to those states as you feel you can reach at the time, and use that state of focus to ask for your spirit guide (or guardian or whatever specific wording you choose) to make their/his/her/it's self known to you.
The rest is patience, listening, stillness, and perseverance. Sometimes it can take a while for the entity/entities to find a way to get your attention. Heck, it took me a year almost to the day to finally have circumstances come together in a way that I could connect with and recognize the presence of my guide.
If you prefer a more formal magical method of calling, there are a few spells on the site here to choose from as well. do a couple searches and see what you connect to. I posted a guide calling a while ago- it might be of some help.
Both are pretty detailed and involved. I like to be thorough. Some tell me a little too much so. But they can be simplified down as well so treat them as guidelines you can take from and adapt to whatever you are already familiar with.