Clients judge you on reliability as much as on quality. A freelancer who always delivers on time, keeps the client informed and handles changes calmly becomes the person clients call first. You do not need special software for this, just a few steady habits.
Track every deadline
Put every deadline into your calendar as soon as it is agreed, with a reminder a day or two before. For each job, work backwards: if the final is due Friday and the client needs a day to review, your draft is due Wednesday, so you must start by Monday. Add those inner dates too.
Keep a simple job list, in a spreadsheet or notebook, with each client, the task, the next deadline and the status: not started, in progress, waiting for client, delivered, paid. Look at it every morning.
Do not overcommit
Saying yes to every job feels good until three deadlines land on the same day. Before accepting new work, check your calendar and be honest about how many hours you have, including time lost to power cuts, network problems, school or family duties. It is better to offer a later date than to promise one you cannot meet.
Update before anyone asks
Send short updates at natural points: when you start, when a draft is ready, and if anything changes. "Good afternoon, the first draft of your newsletter is attached. Please send any changes by Thursday so I can deliver the final on Friday." Clients relax when they do not have to chase you.
If something will delay you, such as a long power outage, tell the client as soon as you know, with a new date.