Gather useful data on the target before you begin the chase. This might include routes they often take, or their favourite hangouts – all of this will make it easier for you to track them.
Dress to blend in. Make sure you follow your target in a crowded area, and dress accordingly, to make sure you look like an ordinary member of the crowd.
Study your quarry carefully so you don’t get confused in the midst of a crowd, and have a clear idea about who you will be following. Take note of what your target is wearing, so you don’t lose them.
Manipulate the crowd to maintain your secrecy. Slip in and out, and hide behind random people, to make sure you remain undetected.
Observe your quarry from a vantage point, in order to get a clear view and avoid suspicion. You might climb up to a bridge or an overpass for this purpose.
Stay focused at all times. Following someone is difficult work, and requires your utmost concentration. Don’t get distracted by anything else around you, and keep the target in your sight at all times.
Maintain a reasonable amount of distance between yourself and your target. This will help you remain hidden, and raise no suspicions.
Try to synchronise your footsteps with those of your target. They are less likely to get suspicious if your footsteps are in time with theirs, and do not cause any noticeable noises.
Make sure you look as discreet as possible in your pursuit. In addition to remaining hidden from your target, ensure that you do not arouse the suspicions of any of the surrounding individuals, as they might warn the target. Stay alert at all times, of both your quarry, and your surroundings.