To see them with human body, you need an activated third eye... You can also see them by visiting Astral plane, however this might be dangerous, and get the attention in some cases...
As MoonCurse said correctly, an extremely easy way that even a beginner can do is by using a Ouija board. On the other hand, Ouija boards represent general summonings in cases you ask generally, eg "is anyone here?" This means anything could show up.
If you want to work up with any spirit-by using of ouija, I don't advice to ask from the first meeting their assistance... I suggest do get known each other for preety much time, and then ask them. There are spirits who are liars or tricksters. They may pretend to be a deceased loved one and so on.
If you decide to work this way, ask spirit's name so you can call it later. Ask information from them... Never trust a spirit from your first meeting if you aren't sure about it... Even if they pretend to be a deceased loved one, keep a balanced impression. Don't show the spirit you bite, but don't show also you don't believe it. For instance, if they say "I am your father, I missed you a lot etc" don't react like starting to cry and "father?! Oh god were have you been, I missed you so much, I love ya so much!..."..rather than "I see, thanks for info".
Call it many times more if you want by their name, and then talk with them. Always keep that balanced state. If they're a Demon, eventually they will get bored and leave...
To understand if an entity lies, you are able to understand through the way their energy manipulates. However, it's hard to tell if someone has little or no experience. It seems you don't have experience, that's why I'm telling you these.
One thing more. I'm suggesting this board because it's fairly easy to use, but I also had to warn you of the dangers. If I were you, I would take the advice of the two posters above about protection..as Reginleif has said, tarot cards or meditation could also help.