Things you need to do is:
1. Don't waste your time with useless things
New players sometimes waste their time by only collecting flowers, killing animals without collecting the resources, running around, swimming without gathering anything, and so on. So, you need to remember that:
A. Craft yourselves several planks
Planks are common use for building in minecraft. To craft planks, just break a log, then craft it just by putting it on a handcrafting slot. You only need one log to get four planks.
B. Craft yourself a bed
Bed is a very important thing in minecraft. If you don't sleep for 3 days, phantons will come and attack you, so just choose peaceful mode for you. You gonna need 3 planks and 3 wools to craft a bed. Just remember, kill 3 sheeps and gather 3 logs to get 3 planks.
C. Build a simple dirt house
If you din't have any time to build a regular house from planks, simply make a dirt house. You don't need torch for this. Just make a 5x5 dirt chamber, put inside a bed or you can just make 4x4 dirt chamber for you to avoid monsters. Make some windows by breaking 3 dirt for you to sight it's day or night. Then, go out and it's worthed for you to take damage, but just run to open land - the monsters will then burn up. Flammable monsters on-day is Zombies and Skeletons. Of course, in minecraft, monsters do not look scary, so it might not be your nightmare.
D. DON'T DIG DOWN
The term of MInecraft says You should never ever dig down. So, if you see any diamond ore below, simply remove the surrounding stones to know there is lava or not. Be careful, also not to dig down to discover the lava area. Then you can get the diamond easily.
