Avoid Pushing
Always try not to push your wave of minions, so you are playing 2 v 1 if you push the line too much they have more options to counter attack if they know you are if your support. Always try to last hit your minions to keep your experience and as much CS as you can.
Use abilities to Farm With
When you are alone in line your long range skills as ADC are very useful to keep your distance with the enemies and be able to farm a little with that, so you don’t risk your position and you don’t give advantage to the others.
CS for XP
It is better to sacrifice a little farm than to lose experience completely, as this will keep you alive a little longer when you are alone in line and not fall behind in level with respect to the enemy ADC and Supp. Keep a safe range in which you can accumulate XP without risking your life, with the champions you get to know what limit you should be at.
As we said before, farm with your skills at a distance, if you can give the last hit with the basics it would be better but if you are at risk it is better to lose the farm than the experience.
Ping if the enemy support roams
Always warn your other lines if the enemy support is not there, with this you keep them aware that he may be helping a target or may be about to attack the middle line which is the most common and take advantage of that. If you manage to see the enemy supp on the map and your line is pushed you can “calmly” attack the enemy ADC since his support is not near.
Play at the opposite side of the lane
Try to keep your distance to the bush that are attached to the wall, because with these you can be an easy target, so keep your game away from there and try to take your wave to that side, with this you always force them to show themselves and you know where they are if they do not want to lose experience the enemy botlane. This clearly if you are 1v2 you have more chances to survive and farm being away from those bush or at least have vision.