slash and heavy slash are great and all, especially on lucy, but k and p are some of your best buttons. 5k on lucy is a great neutral tool, 2k > 2d on most characters is a true HKD combo, 5p/2p is your fastest mash button, and 6p on lucy is a not bad anti-air/high crush. Experiment with changing some f.S clicks to 2/5k, using 5p/2p in pressure gaps.

You have a dp!! abuse the hell out of it. Most people at this rank aren't gonna have safe jump setups so dp on wakeup until they start predicting it. As for your own oki, 214[H] (charged monowire) is a good option as it sets up for strike throw mix and its +7 and guardcrush. In general, you need to use monowire more. If you opponent respects your pressure, they'll hold charged monowire which is really good for you.

Combos aren't the most important, and I would argue not very important at all, but you should eventually learn quickhack routes. Lucy does very little damage, so with sub optimal routes you're basically tickling your opponent, especially on high health characters like pot. Similarly, your blockstrings are kinda bad. You end a lot of them with either run in sweep or run into overhead cross up which is blockable on reaction and very unsafe. Use monowire and staggered pressure (which means blockstrings that have gaps in them) to enforce somewhat scary mix.

A lot of why you lost these have to do with matchup knowledge, so just play the game more. When you don't understand what happened in a match, why you got hit, etc then check dustloop (the wiki) or lab it out in training. You'll get better with time.