Just what exactly are these "critical things"?
When you speak at any reasonably-sized event there will usually be two video monitors on the floor of the stage in front of you. The screen on the left usually shows what is on the big screen behind you so that you never need to turn round. The screen on the right is the countdown clock showing how much time is left. If you are not used to using monitors the problem is that you will not include them in your usual 'scan' of the room and you might miss that the slide didn't change or don't notice the numbers turning read on the timer.
To simulate this setup at home all you need to do is to place on the floor in front of you a laptop to use as the screen monitor and a tablet or mobile phone running a countdown timer. You probably have a timer app already but if not there are many timers on the app store and Google Play.
Plus, of course, you must use a clicker for every practice. For. Every. Practice. If you are not in the habit of using a clicker you can easily forget to move the slides forward. Using a clicker is also much more effective than using the keyboard on a laptop, which distracts the audience. In every presentation you should be using a clicker precisely for this reason, but in big events you simply won't have a choice.
Finally, in most events you will be fitted with a headset microphone. If you are not used to wearing one you might feel uncomfortable when you are miked up, just at the moment of greatest stress before you go on stage. You can reduce this tension to some degree by practicing wearing a headset. You probably don't have one of the expensive mics they use at events -- they usually cost more than $1000 -- but you can use a regular Skype headset. It doesn't need to be good or even to be connected. It is there just to simulate the slight discomfort of wearing one.
If you are planning to use any props make sure that you practice that, too. Where are they going to be when you go onstage? How will you take them out? How will you hold them? How will you get rid of them? All of this needs to be planned and practiced.
Lectures, Workshops, Coaching, Writing
If you'd like to talk about one-to-one coaching for an upcoming event or just to polish your speaking skills you can contact me at 0046 73 089 44 75 or firstname.lastname@example.org I can do speaker coaching face to face in the Stockholm area or through Skype from literally anywhere. There is also the option of group workshops about speaking skills, useful when many people need to learn and budgets are limited.