First off lets be clear I wouldn't call it "Double Life" but rather life here today. That said I'll give a little experience for those younger ones that may be thinking they wish to leave the organization but are too young to do so as they are under age.
Field service was quite the regular occurrence in my household. We never missed. I was petrified because I didn't want to see any of my school friends out in the field. I've always had that gift of gab so it wasn't at all because I was afraid to speak, in fact at times I've had some fun discussions with those out in the field. Rather I just didn't want to see my friends come to the door.
So my partner in crime another brother at the time devised a plan. We would simply talk loudly to whomever we were working with and slightly bend our fingers back as we pressed the door bell. It worked masterfully. I was never caught. Even did it with the CO a few times. No one was the wiser.
There's one catch be prepared because some folks look for witnesses on Sat. am or at least they did so they may see you and open the door anyway LOL.
Girlfriends are always an important topic. I say this because so much is made of the "bloom of youth" but no one asks why God gave such immensely strong urges? It's almost like a sick joke! For myself and my brothers we were a bit cursed. We were pretty boys and got a fair amount of attention. This only made matters worse when it came to remaining clean in the eyes of the congregation. Needless to say we fell short of the ideal of remaining chaste before marriage. At that age having girls literally throw themselves your way is nearly impossible to turn down. I don't care how much prayer you do. The key thing I would stress here is that for whatever reason in those later teen years and into the early 20's those desires are crazy powerful. The urges are natural. You didn't put them there, don't allow others to make you feel evil and conflicted.
But how do you keep a girlfriend without others knowing about it? For one keep your mouth zipped. Don't even tell that close friend in the congregation. Why? Because at some point they'll get caught for something and some how you'll get wrapped up in his FULL confession. If at all possible don't date sisters and NEVER date a sister in your local hall, that's trouble waiting to happen. Non-JW's can never be compelled to out you. For the most part this idea that they are all immoral is a fallacy. They are just as inexperienced and uninformed as you are. Yes there are those floozie girls in high school but I found that most if not all were as I explained.
Play the part and don't allow others to have suspicions. Yes this sounds obvious but it requires work! You have to be prepared for meetings. Show that you've put the time in for any part you may be assigned and do it fully. Your best defense is to seem interested prepared and engaged. This is the toughest part of the double life as you likely don't want to do any of it. However this slight of hand is critical to your plan. When rumor comes around that you were seen here or there or kissing some girl or whatever this smokescreen goes a long long way. Witnesses love to discredit things rather than accept them for what they are. So give them good reason NOT to believe what they are hearing. The issue will likely go away on its own if you do.
Extra curricular activities are a big draw as they give youths the feeling of belonging and not being an outcast. This is for sure a tough sell with witness parents. You may think there's no way my parents will let me be part of a club or play sports. However if you "Play the Part" and are fully engaged with spiritual things there's a chance. Play to the heart explaining that school is difficult. That you're made fun of for really not being allowed to do anything. No holidays, no saluting the flag, no clubs, no sports, no association outside of school, no student council basically you don't exist unless you're in class. Explain that you are doing all you can with your spiritual studies, parts and service. That you will continue to do that however you need a compromise. You need to be able to do some activity just so you can fit in somehow and that you will never let your spiritual responsibilities lapse. Tell them to put you to the test and you'll prove it. This is what I did and it helped me fit in better and not get ridiculed so much. Again though you have to be willing to "Play the Part".
Going incognito today is critical. In my youth there was no caller id, no cell phones, no email essentially no way to track anything. With today's technology you can't be lazy you have to be careful not to leave a digital footprint. There are many ways to do this but again it takes work. You need to have multiple email accounts and social accounts. It's important that both types of accounts appear active. When you browse or are chatting/posting always use "Incognito" or "Private Browsing" modes on your browser. That includes your phone. In fact when you open up your browser you should immediately open private mode. It is a bit of a pain as you have to always login but it will prevent the trail that could ultimately bust you. When you sign up for social accounts NEVER let it attach your mobile number. This will try to sync up your contacts and poke those individuals leaving you exposed. Get a Google voice number on your secondary alias email account. These are free and can be used for SMS confirmation when setting up accounts so as not to expose your REAL mobile. If you really want to take it another step when browsing use TorBrowser.
Lastly, don't feel guilty. You are just wanting to integrate with other humans as intended. You have no malicious intent and you are the same person you've always been. I found that in large part the worst thing about non-JWs was the language. Outside of that they are largely just like you. Don't be ashamed of your sexuality. If God wanted you to not have such strong feelings why'd he give them to you? Those feelings were not your doing. This doesn't mean you should be careless or not exercise reasonable restraint for there are dangerous things out there namely disease. The point though is don't feel guilty about what's natural. I had a friend who was disfellowshipped for immorality. He was so effected by the indoctrination that he couldn't understand after doing all that was asked that he couldn't shut this off. In the end he took his own life because of what he perceived to be failure. I will never forget it as long as I live. This was a good person trying to live up to the standards set before him. He ended up losing life due to liking a girl at the age of 18.