Summoning is not something I have tapped into deeply; however, I do have some prior knowledge of it after seeing it around so many times on the internet.
If you do not know how to make something or someone leave then I wouldn't advise you to let that something or someone enter. Summoning is not something to be taken lightly , in my opinion. It requires a good amount of knowledge and planning. Randomly summoning something is also found disrespectful to some people. I'm surprised people know what "demon" they want to summon anyway. Spirits shouldn't be, according to popular beliefs, summoned without any logical or meaningful reasoning. It is strongly important that you also protect yourself as well. This can be done by creating and being in a circle, a spell, a shield, you name it.
To answer your question, if you know anything about spirits then you'll know that demons are just the same as any other spirit (maybe except for deities) according to different practitioners. I, personally, have found it easy to simply ask a spirit politely to go away if they are in my bedroom or even in the bathroom while I am in it. It works for me but there are various other methods. You may have to search for some online or come up with your own form of banishing something (that is if banishing would be the correct term). If you are a beginner to this then I would definitely go with some more traditional methods such as the Lesser Banishing Ritual of a Pentagram, different chants too, saying verses from a written scripture such as the bible, or even simply praying to your deity or some sacred person/symbol of what you believe in. There are plenty of methods out there so look deep.
The picture of a demon on with the username is paimon i suppose i've already search on them so much that now i already remember it just by watching the picture. Well there are many sites telling you about how to summon them and to send them back,there are even many articles about this on this site. Well for my guidence i can only say that you should speak it with politeness like how you welcome a guest at home,since if it's a goetia demon that you are summoning then you should atleast have solomon's hexagon seal,a wand or dagger,this shall protect you in case of danger for more information you should read the books on the blackcross library,they are really helpful .Also if by any chance you are summoning a demon ranked as a king then you should do it when you really need something important. the demon ranked as dukes are good ones kind of very understanding people.
You must be surprised or maybe not though but just as i read this thread i got straight to the point because i think you have decided whole heartedly i guess,then you'' succeed but first you should read everything that is needed. Remember you should have solomon's seal drawn on a parchment and a pentagram made of silver thay you shoul be wearing at the time,if the sigil of the demon is also engraved on the appropriate metal required of the abou to be summoned. With only shoeing this to the goetia spirit they'll obey you as their master. So it'll be easy if you do it that way.