How can you avoid Project Delays and Slipages on your timeline?

• WBS : creating valued WBS ( work breakdown structure ) based on right and strong scope define, will help in providing  a structure vision for the project and helps to ensure that nothing slips in the cracks. 
• upon WBS you can define the activities then sequences them in network diagram.
• eventually you have to develop & control your schedule based on schedule baseline and doing some changes ( for example compress schedule ) to meet the target, and it should go through integrated change control.

To avoid project delays you have to add extra time to your network diagram. add Project Buffer on the critical path activities and Feeding Buffer on near critical path activities for uncertainty and then you can create your Schedule baseline and communicate it to the stakeholders.

Also you can identify any risk that may effect timeline and create effective response plan.

Use software project tools like JIRA and TFS. They helps to keep track of project development.

Before starting planning is very important. Break project  into smaller module.

Once you modularized project. Write user story, assign task to developer as a sprint. Sprint should be small enough or it complete a module in specific model(in case if you are using MVC software design pattern). 

It is very important to arrange everyday a very short with no description of duration 10-15 meeting aka Scrum meeting. The purpose is just how far they completed in terms of percentage and what difficulties they are facing.

Planning, Scrum and proper update on tracking software will lead accomplishment of project on time. This thing is not so easy but evolve with time.