Benefit of mountain hiking:
1) Fresh air.
2) Exercise.
3) Get to know your friends more.
4) Get to know new friends.
5) Build up team spirit.
6) Total breakaway from being busy on this and that.
7) Get to see some special fauna and flora.
8) Shower in natural water. Back massage under waterfall.

Do not go yet if
a) you are alone.
b) you miss your meal or you forget to bring along some food.
c) your leg muscle is still painful after the last physical exercise.

The team should not be big (not more than 20 people) so that:
a) when there is someone missing from the team it can noticed quickly.
b) you can mingle with each of your team member other more.

Make sure you have been exercising regularly if the trip has a fixed destination and the team will be reluctant to turn back even when you cannot make it. Exercises suitable for mountain hiking should have less impact on knees such as cycling, swimming and going UP the stairs. The exercise should be done daily for at least one month to increase the lactic acid tolerance of your leg muscles. Sore legs are caused by low tolerance towards sudden increase of lactic acid.

If the team or a part of the team can turn back anytime, you can go even you have not been exercising regularly and you can regard this trip as a good start to exercise.

Make sure you will not panic easily and will not think that you are lost.

Do not wear
a) jeans because they will be really heavy when they are wet. Plus you legs are not that agile in jeans.
b) sandals because when they get wet you cannot walk steadily and it is not that safe. Light-weight sandals can be brought along as backup though.

Start the journey early, preferably latest by daybreak.

Things to have for one day round trip
Shoes with the following criteria:
1) Light weight.
2) Good grip, for example basketball shoes has poor grip (and the shoes will be damaged easily if you wear them to hike a mountain). Do not overdo it though by wearing spike shoes. Spike shoes are bad on rocky surface.
3) Can be tied tight on your foot. Slackened shoes are bad idea for mountain hiking.
4) Waterproof.
5) Preferably brown in color (like color of mud).
6) In good condition.
7) It is even better if the shoes are of high cut (above ankle):
a) Will not get wet when you walk over small stream or water puddle.
b) Protection for your ankle against rocks and sticks.
c) The dirt and sand will not get into your shoes easily.
d) The size can be bigger by 2 than your usual size (my size is 42, so 42+2=44) so that when you come down from the mountain the shoes will not make your toes painful. Also after a few hours of hiking the foot may swell and needs space to expand. This is applicable for shoes with high cut only. You cannot walk steadily in bigger shoes with low cut.

A walking stick
a) reduces the vertical impact on the legs so the knees will not hurt.
b) reduces the energy needed by leg muscles to maintain balance.
c) assists in balancing your body when walking on the stepping stones across a stream.
d) lets your arm exercise too.

A retracted trekking pole

The walking stick should have the following criteria:
a) Light weight.
b) As tall as your shoulder.
c) Optional: can be used for self-defense.

If you choose to buy trekking pole (telescopic and shock-absorbing compared to walking stick), it should have the following extra criteria:
a) Not vulnerable to accidental bending.
b) Rounded top for supporting palm.
c) Minimum telescoped length is short enough that it can be hung to backpack.
d) Can be used as a camera support.

I am an adult and I take at least 2 liters  of water for one day round trip. My combination: 1.5 liter of isotonic drink and 0.5 liter of plain water. Be careful on how the bottle is put in your knapsack. You do not want it to drip along the way and the next thing you discover is there is no water in the bottle. Even a new bottle of isotonic drink that you have not opened yet may drip because the moving friction on the cap somehow loosens the cap a little.

Some food that can make you full. It is also good to bring fruit such as apple.

Shirt in eye-catching color.

Swimming trunks (wear the trunks) in case you want to take a shower in the water. Do not bring soap and shampoo. If you wear shorts, you do not even need swimming trunks. Just get into the water with your shirt and shorts (the sweat on your clothing is washed away). Bring along swimming goggles if you want.

Raincoat. Umbrella is not recommended because you will need both of your hands during the hiking. Also, the umbrella may be obstructed by branches.

Mobile phone fully charged.

Sticking plaster (band-aid), iodine, something to wrap up wound. Tissue paper, plastic bag, rubber bands, safety pins.

Rescue whistle (lanyard is not needed) and a small mirror.

I personally do not like leech repellant because it contains chemicals. If you want to wear long trousers, make sure the bottom end of the trouser leg is securable (with tie string or elastic band that wraps around your leg).

Name cards, blank papers and pen in case you want to keep in touch with friends you make on the mountain.

Contact lenses. Glasses can get foggy in the jungle because of the heat from your body. They my also be picked away by branches. If there is clean water at the start point, wear the contact lenses there.

Heavy duty backpack or rucksack preferably designed for mountaineering. Do not bring:
a) normal backpack. It will tear.
b) backpack that has unsecured opening and you have to worry about something dropping off the bag while you walk.
c) single-strap backpack. Stress on one side of the shoulder will make you uncomfortable and you will switch side frequently.

A used toothbrush, if you want to brush off the mud on your shoes before going home.

Towel and clothes for change if you do not want to dirty your car seat.

In the jungle
Try evade branches because there may be:
a) some ants or some other wildlife on the branch that will give you nasty bites.
b) something sharp scratching you.

Do not yell. Remember that is not your territory. And yelling may make other jungle trekkers think that you need help.

Leeches can only be found in rainforest. However you can rarely see leeches. Leeches only come out when the ground is wet and there have been many people walking by. Leeches response to vibration. If a leech sucks on you, do not pull it, burn it or salt it or else it regurgitates into your wound and may cause infection. Just use your thumbnail to very slowly push its sucker mouth away. The wound will bleed without pain because the leech releases anticoagulant and anesthesia. By the way, lemon is a good leech repellent.

Although it is difficult for minor wound e.g. scratches or leech bite to get infected, it is always a good practice to disinfect the wound.

When you stand at a place long enough, some honey bees may come to lick your sweat for salt, do not panic. You can let them continue licking or just blow them away and wipe your sweat dry. When you start walking again, they will not follow you.

Before putting your stuff down, watch if there are ants. You do not want the ants to crawl all over and into your stuff. Also make sure your bag is zipped up because some faunas may like to have some adventure together with you by getting into your bag.

People start to get lost when they think they are lost. So do not ever think that you are lost.

Because this article is about tips I am not going to talk about environmental ethic (for example take all litter home, do not simply light a fire and so on). It should be common sense and you should know. I deeply respect people who exercise it.

Coming down (descending a hill)
To avoid hurting your knees:
a) Do not walk with heavy steps.
b) When the stair is high, squat down and land one foot on the next stair first. Do not jump or stride down.
c) Learn to walk by softly landing the heels first than the toes.