Best usages and practices in Rwanda

1. The first one has got to be the monthly clean up program Umuganda.  This can be a cultural shock. I mean from where I came from closing down 4 hours of precious Saturday time to clean the neighbourhood? But I now have immensely allowed myself to participate, listen and learn.  For foreigners, it looks forced and goes against our ideas of 'freedom'.  But its more than cleaning up, its building a community, getting to know each other in the neighborhood (for Rwandans this comes easy.. their social fabric is quite tight).. but more than socializing, I watched with delight as people came together to solve the issue of children not going to school, suspected drug dealers, and believe it or not broken marriages.  The latter can be quite intrusive, but I saw where a woman was literally thrown out of her house because the husband brought in a woman and she was sleeping in the corridor with little kids.  Obviously a violation of her rights, but the village population endorsed the decision that the man had to look for another house for her, pay her upkeep and her childrens fees.  Now when you consider that she was poor and unemployed, how would she have accessed the justice system for her rights?  It would also have been lengthy, opening her up to being bullied by the husband (and sometimes his family), but in a matter of a meeting a quick decision was taken. 
2. Not littering.  Rwandans have a culture of minimal littering.  They also respect not walking across public green areas like grass.  This has personally inspired me.
3. Rwandans don't eat on the street walking.  Openly visible restaurants are a no-no.  You will hardly find them carrying snacks, chips, etc eating while walking.  Coming from outside this can be puzzling.. but I have found it to be refreshing, as incidences of littering go down, they tend to eat more healthily and with family etc.  If you need to take a snack, there are many covered shops with good seating areas.  Also something curious, Rwandans don't like eating alone.. even in restaurants.  They accompany each other friends/families so its quite refreshing to meet groups sitting together sharing meals which brings in some social bonding.  I realized that one makes better friends this way.. over a meal...
4. Rwandans chat you up in social areas like buses, supermarkets etc just out of the blues.  And they expect you to participate in the conversations.  I have someone come up to me in a supermarket and ask me advise on something and I had to take at least 5 minutes talking and giving her free advise.  At first, I have to admit I was a bit snobbish not being used to it.. but I quickly realized that its quite ordinary I was the problem.  Just keep caution please don't just chat up anyone tho.. use your instincts..
5. Weddings are a big deal.  If you get invited (and you will) please go.  They really appreciate those social etiquettes.  Try and learn how to dress for the wedding from your host so you come in appropriate dressing.  They take it seriously here. 
6. The touchy tribal issue.  My rule.. don't just ask who is who in the country. You will probably not get the right answer (the answer to this is something you will have to experience and learn over time) , plain rude and the issue has hidden connotations that a foreigner would need at least a year minimum to figure them out.  And try to keep away from the stereotypes/movie led stereotypes and just aim to keep an open mind and learn.  At the end, its broad generalizations and stereotypes that rob us the adventure of learning.
7. Try and do some good while you are here.  This country even with its horrible past, is also in some ways quite low when compared to our countries experiences. The government is trying its best, but obviously over stretched with many competing priorities. Don't overdo the good tho, but think sustainable and impactful.  Here are some personal suggestions:
- Paying health insurance for a year for the family.. usually 7 dollars (altho set to be revised upwards) per family per year. 
-sponsoring a young girl for a local school, computer training, useful skill, teaching her how to begin a business, if you can get her the sewing machine, computer etc.. Or just pay school fees in the local school (please not expensive school how will they sustain it when you are not around),
-Assisting with scholastic material for the family
- Assisting with lighting kits for the family in the rural areas.. solar powered, easy to repair, portable... lighting is a huge need in rural rwanda.
-Sponsoring a wheelbarrow/bicycle to a family in rural area.  To transport produce to market or make extra income on the bicycle.
-Supplementing the government program of one cow per household.  Rwandans are culturally attached to cows and this is a gift that keeps on giving.. literally.  Also goats and pigs especially to the women in rural areas to supplement farming income.
Hope this helps!