Group activities are undoubtedly hard because not everyone shares the same work ethic. Here's a list of different types of group mates you may encounter and how to deal:
The Bossy Type
Who: The ones who always seem to have something to say. They devise a way to divide the work without even asking or consulting anyone in the group. They make decisions based on their judgment, and their judgment alone. To put it simply, they couldn't care less about their group mates because they think they know what is best. To them, it has to be done their way or not at all.
How to Deal: Speak up, as an individual or as a group. If they pretend not to hear it, speak up ten times louder. If you don't agree with what he thinks, then say so. Don't keep quiet in front of him only to complain about it behind their back. Confront them, and speak up about your ideas and about how you think things should be done by the group.
Who: The ones who always manage to make someone else do their share of the work. At first, they might even trick you into thinking they are doing something by being active and vocal about their ideas but disappear when it comes to the execution stage. They make up excuses, ask someone else to do it, or even fake a "family emergency" but show up on the day of presentation or submission and pretend they've been with the group every step of the way.
How to Deal: Take action. I suggest you try to reach out first and use any means necessary to push them to do their part but if they still refuse to do so, do something about it. Take off their name off your group's work, inform your professor, or come to a group consensus about what to do with the freeloader group mate. Do not willingly allow someone else's laziness to be excused by your hard work. It's not doing you or that person any good—you're condoning laziness which will make him think that what he is doing is perfectly acceptable.
Who: The ones who always seem to be nowhere to be found. You try their mobile, home, and Facebook messenger but they don't respond. When you finally confront them in person, they make up excuses such as a weak Wi-Fi connection or a lack of load to reply. Basically, they go through every excuse in the book before they actually do their share of the work. As much as emergencies such as these do actually occur, it is important to distinguish between a lie, and an actual emergency.
How to Deal: Find a way to communicate. Make it so that they have absolutely no escape. Get their mobile number, home number, parents' number, or their emergency contact's number even. Try all avenues of communication possible so they can no longer use an excuse.
The Slow Poke
Who: The ones who always seem to move at a glacial place. They submit their part of the work at exactly at the minute of the set deadline, with no time to spare. You have no time to check their part, make sure it's complete and that it's cohesive with the rest.
How to Deal: Come up with a timeline for your group. Set your own individual deadlines. That way, no one can do it just in the nick of time. Making a schedule of tasks for your own group really helps. Allot an extra one or two days before the deadline for any revisions and changes.