You can practise object visualization at any time. If you feel tired, angry or tense during the day there is absolutely no reason why you should not practise this technique as a way of harmonizing the mind. Even five minutes will help to calm the mind.
The best time to practise in order to attain clear visualization is after pranayama. Prana-yama heightens sensitivity and makes inner visualization much easier.
Once again we remind you that you may find this technique a little difficult at first. Don’t become frustrated for this will only lead to mental tension. Merely persevere and the technique will become easier. But time and regular practice are necessary.