There are many different ways, an individual my serve a mission.
Of course there is the traditonal mission 18 months of preaching and teaching.
The church has many other types of Missions, Service, Welfare, Family History, Temple. The first service can take many forms, such as working in the store house etc. A welfare mission can be teaching others basic skills or hygene, this as I understand it can and often leads to opprotunities to teach the gospel to those you are called to serve. The other 2 are pretty self-explanitory.
Keep in mind the church has raised its standards as to what is excpeted of it's full time proslyting (regular) misson, they are much more concerend about the over all health and stability of those that are called to serve. If you feel this is what you want to do than I hope you concider the rigours required from this type of service. I by no means want to discourge your desire to serve and share the gospel. By todays standards I am not sure I would of been called, I found out as I was sitting in my exit interview that by inspiration I was kept close to the mission home in case I lost it, I was being cared for. Keep in mind the Lord is aware of our individual needs and desires and will bless us accoridngly.
Take time to study out your options pray pray pray...talk with your leaders let them know of your longng to serve as they have the gift and power to recieve revalation on your behalf.
Please keep us informend as you mill over this important decision in your life, you have the abilty and chance to touch many lives. ]
Mike