I believe that for most lay Buddhists the challenge isn't so much Nibbana in this life, but rather not to go to hell when they die, not to be born as an animal etc.. Speaking positively: To be born as an intelligent, healthy human baby with loving parents in a place and time good for progress on the Fourfold Path.
Here is a draft list of steps I believe lay Buddhists can take towards this goal:
Five Precepts (partly copied from http://www.buddhanet.net/e-learning/budethics.htm
1) To undertake the training to avoid taking the life of beings.
This precept applies to all living beings not just humans. It includes not buying meat, not using sprays killing insects, not hitting flies and mosquitoes.
2) To undertake the training to avoid taking things not given.
This precept goes further than mere stealing. One should avoid taking anything unless one can be sure that is intended that it is for you. It includes dishonest accounting and marketing, downloading, found objects...
3) To undertake the training to avoid sensual misconduct.
This precept is often mistranslated or misinterpreted as relating only to sexual misconduct but it covers any overindulgence in any sensual pleasure such as gluttony as well as misconduct of a sexual nature. Misconduct doesn't mean "by law" but by your own conscience of what harms other beings. Enjoying consensual sex is not misconduct but too much of it is definitely too much.
4) To undertake the training to refrain from false speech.
As well as avoiding lying and deceiving, this precept covers slander as well as speech which is not beneficial to the welfare of others. It includes profanity, rough and hurting speech.
5) To undertake the training to abstain from substances which cause intoxication and heedlessness.
This precept is in a special category as it does not infer any intrinsic evil in, say, alcohol itself but indulgence in such a substance could be the cause of breaking the other four precepts. These substances (alcohol, marijuana, opiates, synthetic drugs etc.) generally make us less sensitive regarding the other precepts and negatively influence meditation.
The Five Precepts are the basic precepts for day to day training of any lay Buddhist. On special holy days, many Buddhists, especially those following the Theravada tradition, observe three additional precepts with a strengthening of the third precept to be observing strict celibacy. The additional precepts are:
6) To abstain from taking food at inappropriate times.
This would mean following the tradition of Theravadin monks and not eating from noon one day until sunrise the next. Also a healthy way of reducing weight.
7) To abstain from dancing, singing, music and entertainments as well as refraining from the use of perfumes, ornaments and other items used to adorn or beautify the person.
Again, this and the next rule.
8) To undertake the training to abstain from using high or luxurious beds
are rules regularly adopted by lay Buddhists on new moon, half moon and full moon days..
The Buddhist lay follower can train himself by questioning him/herself every night how he/she kept the precepts on the passing day? What could I have done better? The goal is not to be better than the average lay Buddhist we know because there is no guarantee that the "average" Buddhist will not go to hell. The Law of Karma is not more forgiving than a computer game. The goal is to become more and more sensitive regarding morality and to purify our conduct. The reward is (according to Lord Buddha) that in this life people will talk well of us and when we die we will fare well.
Some steps may be difficult: Driving we kill animals, hoovering we kill animals, planting and harvesting we kill animals. To be 100% honest in business isn't easy. What about watching porn? False speech needs constant attention. No beer, no cigarettes, what about coffee and tea?
Some steps are easy: Vegetarian food, organic food, going easy on the earth. Drinking alcohol and smoking will stop by themselves if we meditate a few minutes per day. Meditation will improve our morality and improved morality will help us to meditate. True and gentle speech doesn't cost an arm and a leg.
It all starts with love. Love for for our parents, partners, spouse(s), siblings and children. Treat all human beings as fellow travelers towards a common goal!
Giving is good business. In this universe nothing is ever lost. Giving is your best bank account. Whatever chance to give we face, we just have to put ourselves in the other person's shoes (if he/she has shoes) and do what we would like if we would be born as a person like this. That applies to animals too: Treat your dog as you would like to be treated when reborn as a dog! (There is no guarantee that the "average" Buddhist will be not be reborn as a dog.)
Give food and the necessities of life to monks and nuns, give money to monasteries because in your next life you may be a monk or nun and depend on lay people offering you food and the necessities of life.
How many percents better than no meditation are a few minutes per day? Calculate!
Meditation is free, tested on millions of Buddhists and recommended by 99% of all Buddhist monks and nuns.
Anapanasati - Mindfulness of Breath is easy and effective.
Read one sutta per day. Study Dependent Origination. Study Vimutthi Maggo and Abhidhammattha Sangaha. Learn Pali. Studying is a healthy way of keeping your mind busy with wholesome thoughts.
Draft List - Please criticize, correct and improve! I apologize for the long post.
The Noble Eightfold Path: Proposed to all, imposed on none.