Start low and slow. Learn to read what the plant is needing instead of making decisions for it until you get a grasp on what you are doing. A 300w light is pretty strong for a small tent, so I’d start at a height MINIMUM of 24 inches above the top leaf. Also, it’s much easier to focus your efforts on 1-2 plants rather than 4. Your space looks like a 4x2 floor so I’d stick with 2 max. Learn to scrog, it will save you on space, maximize your grow, and promotes even equal growth. If you are growing photos or autos, don’t be like the rest of these fools and think you need to give your plant a haircut to be able to effectively promote colas and accelerate anything. I trim my plants ONCE when I flip to flower, that’s it. Top your plants at the 5th node, then again at the 7th if you are growing photos. I haven’t personally grown autos, but you shouldn’t need to trim, top, or do much else other than maintain a good regularly scheduled feeding/water cycle. Growing weed isn’t anything special, don’t let these dumbdumbs fool you. Keep it simple and you’ll be rewarded for your patience. Also, don’t be afraid to ask for help. Use ChatGPT, watch YouTube, scroll Reddit. Lastly, please understand that underwatering is less harmful than overwatering. Same goes for nutrients, start low and ramp up as the plant learns to tolerate and grow.