How can I repair my own items?

If you have two of the same item, you can hover over one of them on the inventory screen and press "R". You will be able to combine the durability of the two items to produce one of better quality. Alternatively, you can use weapon repair kits, which are an expendable aid item which raises the durability of your currently equipped weapon by a set amount.

Can I do it with a high repair skill without needing to use a like item?

No - if you repair it yourself, you'll have to sacrifice a like item for parts.

So why am I dumping points in my repair skill?

the higher your repair skill the more repair points the like item gives you, and it also affects how fully you can repair an item.

You really want a repair skill of 50 to make your own "Weapon repair kits". Other than for a perk there really isn't a huge need to take it higher. You can repair weapons to 100% with 50 skill now, or at least I can.

Be warned they're slightly buggy right now. My .357 magnum revolver and service rifle both have mods installed that raise the weapon CND by 50%. If I use a kit on them the CND drops. This kinda svcks in the case of the service rifle and not really a big deal for the revolver. For other weapons that don't have such mods installed the kits are a lifesaver.

Ok thanks! My repair is 53 I believe so I'll stop dumping points in it. What is the perk you mentioned?

If you have 90 repair and the jury rigging perk (available at level 14), you can use vaguely similar items to repair. Like metal armor to repair power armor.

Otherwise, high repair skills effect how much is repaired per repair attempt.

Thanks for the info!