You don't necessarily need to make a portal to project in any manner, though there are ways to get in tune with your subtle bodies or cosmic model based on what path you are in. Northern Tradion Seidhfolk use staves with nine 'knots' in it to help align themselves with the nine main realms of Yggdrasil for pathwalking, journeying, faring forth, etc. Modern folk tend to create portals to help differentiate etheric projection (shifting of consciousness to project the spirit to a place tied to the physical realm) and astral projection (not tied to any physical place).
First, let me ask you some questions about meditation. I do not mean to pry about personal things, though it would help others help you if we know exactly where the issues and strengths are. I also don't mean to belittle, I simply don't know where you are at. Keep in mind that while altered states of consciousness were a part of many cultures, meditation is not universal to every path. It is merely common.
What is your path (this can be religions, spirituality, cosmic model, culture, etc.)?
What do yout think meditation is?
What is your goal for meditation?
Where do you feel you are successful and where do you think the issue is?
There are many methods to achieve an altered state and not all require sitting still and clearing the mind (that works for some people, but not everyone). Knowing how your brain interprets energy will also help.