League of Legends (LoL) Question: Early game advice

Learn to trade properly and take some time to investigate the matchups. Some matchups are very difficult and require some knowledge in order to properly play them. Generally it's also important to focus on farming because any gold advantage can win you the lane.

Avoid trading and all-ins when your opponent has way more minions than you do, a classic mistake is underestimating the damage minions can do. Also, pay attention to the levels as level 2, 3 and 6 are important powerspikes for most champions.

generic game knowledge is my advice.

For example, you must know that as Lux you can't go in an all-in trade vs Talon but you should know how play safely and poke him until you get an advantge over him.

If you learn about most champions' strenghts and weaknesses, then you will do it better.

Maybe you should tell us which lane you play. And wha tis your play style and maybe favorite champs. This can help.
You say you have difficulties with all in combo champs, but do you have examples? I'll give you one.
Riven is an all in top lane champ. That is a strength, but also a weakness cause when she's used all her spells, she is vulnerable, so you can use this information to your advantage, look what she does : to last hit correctly and farm, she is forced to use her Q and sometimes her W. When it is over you can zone her. Mean attack her, normally she will back a little cause she is under CD, and this give you enough time to farm low life creeps. You cannot reasonnably kill her unless she is really low life but you can damage her enough to make her go back under her tower or far enough to take your cs last hit.
Also, you can play "super safe" like you said but not lose too much CS, that is something to learn to do : if the creeps are under your turret, you have to learn how to kill them before the turrets does. This is possible really, and so you dont fall that much behind.
So again, I'm not sure this will answer you, but I have to few info about which champs you play and the one you dont like to face, so basically, know the weaknesses and strengths of your opponents to know when you can take last hits without beeing in death danger.

I'm by no means a pro player, for I am currently only in Bronze 1. However, I do not find it difficult to lane unless I am being countered hard, in which case I play it safe and passively making sure only to get last hits on minions if it doesn't mean my life. At which point they should have pushed to my turret where by our jungle should find this an opportune time to gank. If jungle is not able to gank because he busy with other lanes who are also struggling then you just fight under turret and do your best. He should be able to help you eventually. If your other team mates are doing bad then, I'd say you can't really beat yourself up about bad team mates.

If your bot make sure to pick an ADC (if not support), mid typically an AP champ or the few AD mid champs and top a top champ. Try to counter as often as you can in draft picks and if its just a random scrimmage well, hope you don't get a champ that counters you to bad. Even a hard counter isn't a guarantee you will lose your lane. Again, just play it safe.

Wards are extremely vital. You don't want to get ganked on. If you are pushing your lane hard trying to be aggressive then ward river, to see incoming mid/jungle who (if they are decent players) will try to help win back their lane. Warding and anti-warding has always been a standard but now with the most recent update its become more accessible and in some way easier for people to be part of the warding games.

Also be sure you know your champ inside and out. Exploiting your advantages and knowing your disadvantages, as well as when to go in, when to save someone/kill and when to bail. These things are what make lol difficult. A team with accurate knowledge of these things would be undefeated.