A first practicality is to establish when the best realistic time could be. We have various biblical examples of morning and evening, as well as occasional all-night vigils. Morning has been put forth as ideal because that is the start of the new day and we can dedicate it to God straight away. However, for families, or those working night shifts, the morning may not be best. Parents with children will usually try to have personal devotions while the children are asleep, or at school. The general guiding principle is to find the time when we are best able to give God our undivided attention. The length of time varies; the amount of time is not so crucial as the quality.
Place may be a determining factor. If we live alone, or in a large house, to give just two examples, then solitude for time with God should not be difficult to obtain. If space and silence are luxuries, then we may have to be more adaptable. I find that I have to adjust depending on where I am living. While sharing a room at University, I had a quiet corner in which I faced the wall and put in earplugs. I often still use earplugs when I have had my own room while working - because of outside noise. I confess that I have had quiet times on trains, buses and the London Underground. The day is not really right until I have met with God in some way, and the whereabouts cease to matter when I realise my need to come to Him afresh.
Another factor worth mentioning is the method of spending time with God. The time and the place available may determine how this happens. Two popular ways are what I call 1) guiding notes and 2) inductive questions. Many people use a daily devotional guide with their Bible - Scripture Union notes are probably the best known. The inductive type (such as Search the Scriptures) involves answering questions on a Bible passage with no given commentary. Both of these have their own advantages and disadvantages, and a certain degree of literacy is necessary. Keeping a diary or journal of one's quiet time can be helpful; for example, writing what the Bible teaches and one's own prayers. I do this as a way of remembering and being able to have a record of seeing how God answers prayer. However, other people may cringe at the thought of more words to put on paper, or even find it hard to concentrate on reading in the first place.
We must not forget that this time is not primarily one of study. We are meeting with God, and the key is to have ease of communication with Him while not diminishing our reverence. For some people, writing and reading aid that communication. Others may find that having the Bible on cassettes or in a picture format may be more helpful. Scripture set to music can be another variation on taking in God's Word. I have also found that I learn so much about Him from the natural world. However, going for long walks every day by the sea, for instance, is a luxury for most of us. We can think of other methods appropriate for where we live. With all of these ideas, the aim is to build up our relationship with God in Christ by the Holy Spirit.
I wish to conclude with comments on the 'crisis' periods (not to be confused with rebellion!) when time, place and method may be completely thrown askew by exceptional circumstances. In these periods, concentration may be minimal. In fact, we may find ourselves unable to pray or open the Bible for an extended period. Illness or tragedy can cause the lapse.
First, when our hearts are right with God, we know He will understand, and we must not torture ourselves with misplaced guilt.
Secondly, we can be assured of the prayers of others, and can be strengthened by the many promises God makes that He will be with us. He knows who are truly His, always.