Let's start with what your three mocks are telling you. A 305, then 405, then 355 isn't a downward trend or a plateau. It's the pattern you see when the underlying content hasn't been built yet, so the score swings based on which questions happen to come up. At this stage, mocks are
measuring you, not
teaching you, and they'll keep bouncing until the foundation underneath them is solid. So the shift is this: you don't raise your score by taking more mocks and hoping the number climbs. You raise it by building the content, and the score follows.
Looking at the 355 breakdown, your Quant at 62 is the furthest from where it needs to be, with Verbal at 73 and Data Insights at 67 a bit higher, though all three still need real work. None of these is at a level you'd just maintain. Quant is probably your best place to start, both because it's lowest and because a lot of Data Insights rests on the same quantitative foundation.
As for how to build that content: take one topic at a time, learn it thoroughly, then practice only that topic, untimed, until your accuracy is consistently high before moving on. For every miss, figure out why, whether it was a concept gap, a misread, a careless error, or a trap answer. Redo the ones you got wrong from scratch a few days later to confirm the fix held. Add timing only once a topic is solid, and mix topics into broader sets only after several are solid. Hold off on more mocks for now and save your remaining official ones for later.
On whether a course helps: given that you're self-prepping with no structure and have gaps across all three sections, yes, a structured course would help you a lot. Course quality varies enormously, so choose carefully rather than stitching together free materials. Look for a sequenced topic-by-topic curriculum, deep content coverage, analytics and error review, mastery-based progression that confirms you've learned a topic before pushing ahead, and increasingly, AI coaching done well, the kind that lets you upload your work so it can diagnose where your reasoning broke down. That last piece has become a real differentiator worth weighing. A good course is also much of what you want from a mentor: a guided path instead of figuring out the order and gaps yourself.
Regarding timelines, 4 weeks is very tight. It will get you real foundations and move you up, but I wouldn't count on a strong score in such limited time. If your test date has any flexibility, giving yourself more time is the single highest-impact decision you can make. If it's fixed, build Quant and Data Insights as deeply as you can, treat this as a first attempt, and remember you control which scores schools see.
Either way, the move is the same: stop taking mocks for now, commit to a structured topic-by-topic build starting with Quant, and study for accuracy before speed.
This article walks through that content-first structure in detail:
How to Make a GMAT Study Plan.
cumvitae
Hi, I've been doing a self prep for GMAT FE exam and have take a couple of mock exams and I've got 305, 405 and 355 on my 3 attempts. In my last attempt of 355, here's the breakdown of each section: QR:62, VR: 73, DI: 67.
I'm looking for a mentor to increase my score as I just have 4 weeks to give the exam. Can someone please share the insights on how I can improve?
P.S: I've not joined any course and I'm not sure if it really helps..