To make sure that your automated test suite is successful, below are our recommandations.
1.) Don't make it too complicated. - We have seen in many cases that the orgranisation write lots of wrapper on top of the tool. It will make it more complicated to use. Keep it simple.
2.) Choose your programming language wisely - Make sure that you choose programming language that everyone can work on.
3.) Have a source code management system implemented - Having a source management system is very important. It will help you scale your team.
4.) Manual test cases should be optimized - We usually automate 80% of manual suite. Make sure that manual test case are optimized.
5.) Maintain object repository - Its very critical to maintain object repository from the begining. It will help you reduce maintainance work in the future.
6.) Make sure that you use right reporting tool in case of you are using open source testing tool.
7.) Add proper logs to the suite. It will help you determine errors.
8.) Use CI - Make sure that you setup a CI server and run your code regularly. This way you can make sure that by the time your all tests are automated, everything works fine.
Feel free to provide your views in the comment section below.