The first step to making an achievable goal is to know what a goal is. A goal is a point of intention you wish to aim your efforts to. Once you have the mindset that you want to pursue a goal, setting down and making a plan of action is the starting point.
Ask yourself these simple questions when first writing out your plan of action:
What is the end result I want to achieve?
Is this a goal that I have the means of achieving?
How long will it take me to achieve?
What sacrifices will I have to make to achieve this goal?
What will I do if I hit a "snag in the road"?
If you can confidently answer these questions then you are ready to write you goal plan. The best plan is to break your long term goal down into sub goals. This helps the overall outcome of the goal easier to achieve. When you simply have one long term goal plan you can become bored with the plan or lose self-esteem because you feel that you are not achieving anything. Try breaking the larger goal down into three month periods. For every period, set a sub goal that acts as a "stepping stone" to getting to the larger goal. An easy way of deciding how to set these goals is to write out each thing that needs to be achieved in order to make it to the main goal.
For example: John has decided to that he wants a new car but doesn't have the money for a down payment. He would like to buy a car by the end of the year. He has nine months left in the year. He writes out each step he will need to go through in order to save up the money he needs. (1) pack lunch instead of buying it-saves $60 monthly (2) put $20 in savings from every check - saves $80 monthly (3) cut bills down by lowering unneeded services on cable and phone- saves $125 monthly.
John's Goal Plan: June: have $670 saved, September: have $1340 saved, Dec: have $2010 saved and put down payment on new car!
Once you've broke down the steps you will have to go through in order to reach your goal you have to stick with it. Having a buddy for support is a good idea. They don't necessarily have to have the same goal as you, but it does need to be a person who can help encourage you to pursue your goal. A support team will also give you drive. Knowing that there is someone else who knows your goal and is watching you as you achieve each step will give you the confidence to push forward with each sub goal. You'll find that after a few successful achieved sub goals that you'll have the desire to keep going.