You will start to sweat more, especially under the arms, it is important to start using deodorants. The onset of puberty will see you having erections more frequently. On occasions these erections may be spontaneous. This can seem embarrassing but it is perfectly natural. You may wake up and think you have wet the bed, but you haven't, the sticky liquid is semen.
Wet dreams are a natural part of puberty - they happen to all guys.
For girls, during puberty you will notice your body begin to change in a number of ways. The production of the female hormone called oestrogen increases during puberty. It is oestrogen which drives the changes in your body. You may have a sudden growth spurt and see noticeable changes in your body shape. Females will develop hair under their arms and around their vagina.