The first thing to do is to cut down about 3-4 trees and turn 4 peices of wood into planks so you have 16 wooden planks. Then make a crafting table and turn 4 planks into sticks so you have 8 sticks. Now craft a wooden pick and go mine out about 19 blocks of cobble stone and then craft a stone sword, stone pick, stone axe, stone shovle and stone hoe. That will leave you with 8 blocks of cobble left that you should craft into a furnace.

Now either mine out some dirt, cobble or wood and make a 5x5x3 hut with a flat roof and mine out a 2 blocks wide and 2 blocks deep trench around the hut. Now turn 4 more peicres of wood into planks and put half of your remaining planks into the bottom of the furnace and put logs into the top half to make charcoal.

Hopefully you now have about 10-20 peices of charcoal depending on how much wood you had left. Use about 5 peices with 5 sticks to make 20 torches and put 2 two torches inside the hut and put the rest around the area. Now go cut down more trees and either kill animals or destroy grass to gain seeds. 

If you got meat (Pork, beef or chicken) Cook them in the furnace with the charcoal.
If you got seeds, go to the nearest water source and till the soil around the edge of the water and 2 blocks out and plant all the seeds you have.

Now with the wood you just obtained earlier create a single chest a wooden door and 2 hatches. Place the hatches infront of the door of your hut so there is one either side of trench so it acts like a draw bridge and then place the door in.
(If you havent already place your chest, work bench and furnace on the inside of your hut)

Now night should be approaching so you need to prepare. Make sure you have a food source so apples from the decaying trees is good or any other food you have is also ok. Make sure you replant trees aswell and keep the remaining saplings as fuel for your furnace. If you had killed cows and obtained leather try make as much armour as possible. If you had killed sheep and obtained 3 wool then use that and turn it into a bed and sleep the night.

Lastly, with some of your remaining wood turn it into sticks and make 4 fences. Then put a 1x1x1 hole in the middle of each wall and replace with a fence post to act as makeshift windows so skeletons can't shoot you. Finally stay in your hut till the night is over and then collect all of the mob drops in the morning.