If you are the owner and you are a qualified pilot and the aircraft is certified in the private category, I believe you can do you own 50Hr. check. However, you must stick strictly to the items in the maintenance schedule. Anything more you need to find a licenced engineer. Some engineers will do the odd 50hr check for you, (given the above critera), away from a maintenance base for a bit of pocket money, if you don't feel comfortable enough to do it yourself. Remember it is your life!!
If you decide to have a go, you are not allowed to disturb any locking devices and strictly not allowed to disturb any flying controls or engine controls except to establish full/free movement and to look for problems such a ware or excessive free-play or fouling.
If you find you are permitted to do your own check, then I would advise you pay an engineer to show you the first one.
Your first check should in fact be to understand the aircraft log book and the maintenance schedule that it has to comply with. I believe that the requirements for certification are in that.