I always end up in the 8th place every game

..... You understand how impossible it is for anyone to tell you what you're doing wrong?

Tell us what you do, or did.

Ask questions.

Well first of all your sample size is too small to say anything. At 5 matches you can't even say you've played TFT yet, let alone that you always lose.

Some generic tips: -Don't waste much gold early on. Try to save up, and pay attention to your interest (Try not to use gold if it affects your interest in the early game). -Try to take advantage of class/origin bonuses when possible (And in the early game, you usually need to have some defense... Meaning knights, guardians, or brawlers). -Using carousel to get good items for certain champions can often be more useful than going for the champions themselves (You need to start figuring out which items are best on which champions though). If you're in last place, you actually have a massive advantage here, since you pick first (So it's often a good idea to grab rarer items while you can). -Remember that losing some health in the early game is not a big deal, but you should try to minimize the damage as much as possible. Losing against minions/monsters is always bad though... Make sure to avoid that.