I often neglect to pray, usually because I am too tired, busy, or just lazy. When I do stand up to pray, I often find myself unable to continue for very long. I really want to pray, but I just find myself unable to do so at times.
The brethren asked Abba Agathon "Amongst all our different activities, father, which is the virtue that requires the greatest effort?' He answered: 'Forgive me, but I think there is no labor greater than praying to God. For every time a man wants to pray, his enemies the demons try to prevent him; for they know that nothing obstructs them so much as prayer to God. In everything else that a man undertakes, if he perseveres he will attain rest. But in order to pray a man must struggle to his last breath" (From The Sayings of the Desert Fathers)
Praying diligently is a struggle against the devil. St. Luke says, "Then He spoke a parable to them, that men always ought to pray and not lose heart" (Lk 18:1) and St. Paul says, "Pray without ceasing" (1 Thess 5:17).
You need to set a specific time for prayer daily. It is best if it is first thing in the morning. Make an effort to wake up half an hour early and start your day with prayer. You have to keep in mind that you can defeat the devil who will try to discourage you from waking up early, and that you will pray later during the day. These are all excuses the devil brings to your mind in order to tempt you and defeat you. Do not succumb to his trials. Be firm and repeat to yourself "I can do all things through Christ who strengthens me" (Phil 4:13).
Once you start praying, the devil will make you go astray with your thoughts or make you feel bored of prayer. Again do not let him win this battle. If you wonder away repeat again and again the same prayer or psalm trying each time to concentrate on it and pray to God at this moment to let you focus on your prayers.
You may want to start from tomorrow with a goal of only 10 minutes of prayer and as you achieve this goal by the end of the week you can increase the time. Do not give up but take it slowly and surely. 'With prayers' you will be able to live the life of prayer and overcome your sins.