how-to-prevent-erection-problems

For many men, lifestyle changes can help:

Cut down on smoking, alcohol, and illegal drugs.
Get plenty of rest and take time to relax.
Exercise and eat a healthy diet to maintain good circulation.
Use safe sex practices, which reduces fear of HIV and STDs.
Talk openly to your partner about sex and your relationship. If you are unable to do this, counseling can help.
Couples who cannot talk to each other are likely to have problems with sexual intimacy. Men who have trouble communicating their feelings may find it difficult to share with their partner any anxieties about their sexual performance. In these circumstances, counseling can be very helpful for both you and your partner.

Source
http://www.nlm.nih.gov/medlineplus/ency/article/003164.htm