Loneliness, especially psychological loneliness is a prevalent force in the novel. Lennie is alone because he is so different mentally, he processes information differently has trouble making friends. He copes by being generally friendly to people, although his reactions tend to drive people away. Curley's wife is lonely and seeks to cope with her loneliness by attracting the attention of men by using questionable methods, like being overtly sexual. Crooks is lonely because he is colored and has been singled out by being put in a separate bunk. He copes with his loneliness by wallowing in it alone and driving others away, except for Candy, Lennie, and George. Candy is lonely because he is physically handicapped and can't do the same things the other men on the ranch can. He copes by drawing inward and putting on a strong front. He is very submissive in his combat against loneliness. George is lonely because he is constantly on the move and protecting Lennie which doesn't lend to many lasting friendships. George copes with his loneliness by dreaming of owning his own ranch and dreaming of the freedom he would have, even with Lennie, if he had his own land and made his own rules.
Loneliness is a very personal emotion that everyone deals with very differently just like in this novel. People feel lonely for very different reasons as well. In this book there are so many different reasons people feel lonely that almost everyone who has felt alone can find a character to relate to.
To discuss some examples from the novel, Curly's wife tries to ease her loneliness by hanging around the barn to try to find someone to talk to....of course we know how that works out for her.
Candy found solace in his dog and again that doesn't work out either.
All of the supporting characters are lonely in some way, which of course contrasts the relationship between Lennie and George.
You say "other ways", but I'm not sure which ways you've already identified. So, if I'm repeating someone, I apologize.
I think some things people do to avoid loneliness is to find hobbies. Sometimes those hobbies involve other people, sometimes they don't. When they do, then the person is made less lonely by the interaction. Why the hobbies doen't involve others, then the person is distracted by their loneliness by the activity.
Examples of hobbies - sports teams, art and crafts clubs, physical activities (golf, skiing, etc.), stamp collecting, dance, etc..
People will often put all their energy into their work in order to avoid loneliness too. I would call this a negative example of how to overcome the problem. Although being a hard worker is a respectable trait, all people should have more things in their life than just their job.
The best way to stop being lonely is go out and meet people. Get involved in hobbies, or consider volunteering for local programs - such as at a nursing home or school or library. There are many opportunities in every town. These ways encourage interaction, and can also bring a sense of satisfaction from helping others or accomplishing a goal.
who is most alone/lonely