When you're organizing a march in support of a certain cause that is important to you, your to-do list will typically include recruiting people who share the same belief about the cause as you, as well as perhaps getting signs, T-shirts, and other similar materials together. Part of your organization process should be to talk to your participants about the risk of protesters. Depending on the cause that you're supporting, it's possible that there will be people who meet with your march along its route to protest what you're supporting. Making your group aware of this risk and providing the following guidelines can minimize the potential for conflicts.
One of the simplest ways that your march participants can avoid getting into conflict with those who may be protesting your presence is to keep moving. A big benefit of marching is that you're continuously moving, so unless someone is prepared to walk alongside you, your group can move past a protestor quickly and largely without incident. As you organize the event, make sure that your group members know that the best way to diffuse any potential problems is to simply continue to walk, rather than stop.
It will be tempting for your group members to engage with any protestors, but such situations are apt to turn into conflicts that involve shouting. This isn't an ideal scenario because you want your group to be calm and focused on the issue that you feel strongly about. Remind your members that they shouldn't engage with any protestors. They may feel like a conversation is a chance to change a protestor's mind, but there's a good chance that the protestor isn't standing along your march route with an open mind. No good will come out of going back and forth with protestors.
Record Any Conflicts
While your group should ignore protestors as much as possible, you should empower your members to use their smartphones to record any particularly hostile encounters. The presence of some phones may actually prevent the protestors from acting too aggressively, which is important. However, should someone along the march route throw something at your group or otherwise do something that borders on illegal behavior, you'll have footage that you can pass to the authorities. Given that the cameras will be rolling, it's especially important to emphasize to your group the importance of being calm, professional, and not getting goaded into a conflict.