The process of building a walk in shower can be tedious, but every step is important and should never be rushed. Depending on what kind of shower you're installing, there may be fewer steps, or more steps...how much patience you can bring to the project will be critical in ensuring a favorable outcome.
You can buy completely pre-fabricated units in different walk in shower designs that you literally just drop into place and glue in. However, you really need to prepare the spot where you'll put it carefully. The pipes and openings for faucet, knobs and shower head must be perfectly aligned. The floor must be perfectly level. The walls to which the shower will be adhered must be solid and cured if recently built. Patiently paying attention to every detail before putting the walk in shower in place will ensure a professional installation.
The same is true of semi-framed walk-in shower, or other walk in shower kits that comes even partially fabricated. Proper preparation of the space is essential. Additionally, the glue and caulk must be allowed to cure at the optimal temperature range for as long as the manufacturer directs before using the shower. So however anxious you are to use your new shower, patience here will pay off in a much longer life for your new shower later.
If you have decided to go with a completely customized shower that you install yourself, maybe using glass block or tile, then you will need even more patience. Accurate measurement and careful positioning of each tile is necessary, and this can only be done by a non-rushed, patient person. It doesn't require any great skill (although professional contractors would surely disagree with that statement) but if you are patient enough and willing to redo your work if it isn't quite right, you can completely install a custom tiled walk in shower yourself and no one would know you did it. You can find a lot of the materials you need in a walk in shower shop.
Because you need to let the grout, mortar, adhesive and caulk all cure properly before proceeding to the next step, a tiled or glass block walk in shower requires a lot longer to install. This is not a weekend project! You will need to be able to bathe elsewhere for at least two weeks while you build this in your spare time. Again, patience will pay off in the long run, so keep the faith.