I've been working remotely since September of 2011, and I've gotten questions both from coworkers and acquaintances about how to overcome some of the challenges.
I don't think I really know how - from my perspective, it revolves highly around the personalities of the people involved, and the established culture of a company.
For myself, it worked best when I worked in 100% remote companies. There was no office for people to go in to, and thus all communications were funneled through emails, IRC, the bug tracker, and VoIP/video chats. No fallback to rolling your chair over to the other cube was available.
This is both good and bad. Good because it means that there aren't necessarily the distractions of other coworkers constantly interrupting work, which for programming can be pretty bad for maintaining flow and being productive. Bad because it means that you as a worker need to keep yourself more disciplined if you're working at home with all your home distractions, as well as monitoring yourself for things like burnout and getting stuck on a problem where you need help.
As a remote worker, you need to be comfortable with raising your hand and saying, "I need help with this," or "I'm frustrated, can we talk?" If you don't, others are going to have a much harder time picking up on it than if they see you in person getting mad at the computer or whiteboard. For myself, I think this has been the hardest part. I'm very much an introvert, and though I like to bitch a lot on twitter, I have a hard time catching myself when I feel burnt out and actually communicating that to others in order to get help.
I also think it's worthwhile, whether you're in office or remote, to take some kind of break. A vacation or staycation or whatever, but get away from work for a bit. Try to find a way to put it out of your mind.
Most of the companies with a significant percentage of remote workers also make an effort to bring in the remote workers from out of town in order to give them face time together. For example, I know GitHub does annual gatherings where the point is to not necessarily work, but to hang out and socialize with each other.
From my perspective, this is probably the most effective team building there is. Not forcing people to get along, but bringing them together in a central place and letting them have fun in a relaxed atmosphere.
I also think the hiring process is crucial when dealing with remote workers. As much as possible, introducing potential hires to members of the team other than just managers is crucial to success, so that the team gets to know the potential hire and vice versa.
Without doing this, you're increasing your likelihood of personality clashes after hiring.
I really think this is just good practice regardless of whether the potential hire is remote or not. It gives the new person a much better idea of what the team is actually like, instead of just what the hiring person says, and demonstrates a commitment to an atmosphere where the team makes decisions, not just the managers.
I know GitHub uses their drinkups as part of this process in order to get to know a new hire, and I also know a lot of other engineering shops are including it more and more into their hiring process. In my opinion, GitHub's gatherings are able to about 'just having fun' because they do a lot of work to identify personality compatibility early on in the process
Some more good thoughts on this are from Rands. He makes a strong argument that a lot of the tools we think we need for remote workers can in fact be a hindrance - the delays in video/phone chat in meetings can be killer, as I've found on both sides.
For myself, I've found that being on the remote end it's usually easier to not interject, which in turn becomes a problem, since my feedback isn't getting registered at the time it's most relevant.