Tips for Getting Started
Assuming this is anything like the previous Dark Souls games. Get a longsword and a 100% physical block shield. Make sure you have the minimum strength and dexterity to wield them and then start pumping your HP and stamina stats (used to be vit and end, but they changed it to vig and end)
The higher hp lets you survive more hits, giving you more chances to heal. The higher stamina lets you block harder hits and means taking swipes at the enemy wont be harming your overall stamina as much.
Later you should get strength so you can swap to bigger shields that will have higher stability. Stability on a shield means you lose less stamina when you block an attack, its necessary for blocking the later bosses or they will break your guard.
Because your strength and dexterity are low you will have low damage on your attacks. However if you get a raw or elemental longsword your weapon will have fixed damage that is more or less unaffected by strength or dexterity. It wont be as high as if you had a normal longsword and raised strength and dexterity very high, but its almost as good and lets you focus on defensive stats.
Also stay unarmoured or lightly armoured. You want to keep your overall encumbrance below 25%. This will make you invincible while performing a dodge roll for the first half of the rolling animation. Sometimes it costs less stamina to roll through an attack than block it, but its dangerous if you dont get the timing right.
Tactics wise: The most important thing to know is that whenever you find a new enemy or boss you need to learn its moveset first. Get close so it starts an attack then back off with your shield raised and watch. Learn all the moves and timings before you try to kill it. You can dodge through most attacks if you are unarmoured or very lightly armoured, but you need to memorise the attacks and timings before you try otherwise you will be relying on reflexes and luck.
Also be aware that most bosses get extra attacks when their HP goes below half. The first time you drop a boss HP below half you should go back into learning mode and start backing off and watching their attack patterns.
Last Note: You might want to get enough int early on for the first mage spell. In these games you can usually fire it many times and it does respectable damage even with the minimum int required to fire it. You can use it for enemies that are a pain to engage in melee and wear them down from a safe distance. Unlike arrows it cannot be blocked completely since the damage is magic, not physical. There are times you encounter enemies in annoying positions like on narrow pathways or in a gauntlet or a ambush points, especially when they have shields. Being able to just chip them down with magic missiles is great. You can use it to finish off a low HP boss when you have run out of healing items if you know you can back off until it uses an attack that leaves it open then shoot it from outside its attack range.
You can get the minimum faith for a heal spell as well which allows you to save on healing flasks by healing between fights with healing magic. I find this less useful than having magic missile but its a good choice and you can always take both if you like, just dont try to cast it in a fight it takes too long.